research project - final report form - Food Standards Agency

RESEARCH PROJECT - FINAL REPORT FORM

Section 1 : Project Details

1.1 Agency Project Code(s) MC1003 / FS245010

1.2 Project Title (from Contract)

Outcomes and values of current ante and post-mortem inspection tasks & assessment of the benefits to public and animal health of post-mortem inspection of green offal in red meat species at slaughter.

1.3 Project start date 01 May 2010

1.4 Project end date 31 January 2011

1.5 Date final report submitted 11 February 2011

1.6

Agency Project Officer Carles Orri

1.7 Name and address of Lead Contractor

Royal Veterinary College Hawkshead Lane North Mymms Hatfield AL9 7TA Herts, UK

1.8 Lead Contractor Project Leader

Name Silvia Alonso

Telephone 0044 (0) 1707 666 528

FAX 0044 (0) 1707 666 574

E-mail [email protected]

E-mail

1.9 Collaborating Partners or

sub-contractors

Danish Agriculture and Food Council (DAFC), Denmark Food Institute for Risk Analysis, Germany

Section 2: Key Findings - Executive Summary

The aim of this research project is to address the following policy questions:

a) what is the value of current ante and post-mortem inspection tasks; and

b) what are the contributions to public health, animal health and welfare of post-mortem inspection of

green offal in red meat species at slaughter.

These two questions were merged into one project as most of the preparatory work was common to

both pieces of research. However, findings are reported separately so as to provide a cohesive

response to each individual question.

Background

The current meat inspection (MI) system for cattle, sheep and pigs in Europe was established at the

end of the 19th century with the aim to protect consumers from diseases such as tuberculosis,

brucellosis and human teaniasis acquired from animals.

This MI system consists of checking animals and their organs for lesions and abnormalities, which is

done visually, through palpation or incision as required. Post-mortem inspection relies solely on the

detection of macroscopic lesions (visible to the naked eye) caused by pathogens or other hazards in

the carcase and organs of affected animals. After targeted effort, including surveillance and

eradication programmes, many of these diseases have either been eradicated in Europe, or their

prevalence has been greatly reduced, decreasing their significance to public and animal health.

MI requirements are set out in directly applicable EC regulations. The current MI system allows for

limited flexibility and does not follow risk assessment principles. This is a costly system that requires

a great deal of public resources dedicated to carcase inspection.

Rationale and Objectives

Today, the most important meatborne hazards causing human disease are Campylobacter,

Salmonella, Yersinia and E. coli. These do not typically cause clinical disease nor are they visible to

the naked eye, and are therefore unlikely to be effectively detected by traditional MI tasks. They are

usually transmitted to the carcase through faecal or other contamination routes during the slaughter

process. In this context, the MI system as a whole, or some MI tasks in particular, may no longer be

fit for purpose. Thus, MI should be reviewed and more effective ways of addressing the new threats

to human health should be considered. In addition to that, consideration should be given to the

potential contribution of MI tasks to cross-contamination of carcases.

Notwithstanding this, many important hazards and conditions associated with animal health (including

endemic and exotic infectious diseases) and animal welfare can be detected at the slaughterhouse.

This adds complexity to the study of the contribution of each MI task to protecting animals and

humans.

Elimination of MI tasks that do not contribute meaningfully to the detection of hazards could

potentially free resources that could be used elsewhere to control meatborne diseases. However, this

might result in an increased risk to humans and animals from pathogens currently being controlled. In

order to evaluate the contribution of MI to public health, animal health and welfare, an assessment of

the effectiveness of all MI tasks in relation to the most important hazards must be carried out.

Approach

Work has been carried out in three stages:

1) Identification of relevant hazards

The most important public health (PH), animal health (AH) and animal welfare (AW) hazards

associated with red meat production (cattle, sheep and pigs) were identified using available scientific

literature and published reports. Legally required MI tasks (both ante-mortem, AM and post-mortem,

PM) for these three species were mapped and their potential to detect the identified hazards was

evaluated.

2) Development of a tool to evaluate the effectiveness of the MI system

This step addresses the first policy question. A tool was developed for the qualitative assessment of

the detection capacity of each MI task. The assessment of effectiveness is mainly based on two

parameters: the Sensitivity (Se) and the Positive Predictive Value (PPV). Sensitivity is defined as the

proportion of positive (i.e. infected) carcases that are identified as positive by the MI task. PPV is the

proportion of carcases identified as positive that are actually positive. The combination of these two

parameters provides a general estimate of the capacity of a task to effectively detect a hazard. For

this model, literature, available databases and expert opinion were used to obtain Se and PPV

estimates for each task. These were then transformed into qualitative estimates (very low, low,

medium, high and very high), and combined to produce an overall qualitative score which defined the

task‟s “capacity of detection” of a hazard. The qualitative assessment tool was applied to a selection

of hazards with the purpose of validating the model. The hazards included were:

Public health - Salmonella in pigs and Toxoplasmosis in sheep;

Animal health - M. bovis (bTB), M. avium subsp paratuberculosis (MAP) in cattle and Classical Swine Fever in pigs;

Animal welfare - Tail Biting and Hernia in pigs.

3) Risk assessment of green offal inspection

This step relates to the second policy question. An assessment of the risk to animals and humans

from changes in MI practices, specifically in green offal inspection, was carried out for the

abovementioned selection of hazards, using the Codex Alimentarius risk assessment framework. A

risk pathway mapping all the steps of red meat production from lairage to chilling of the carcase was

developed. Three main factors were considered for each step: presence of a hazard, detection of the

hazard and actions undertaken as a result of detecting the hazard. Current MI requirements dictate

that green offal (including intestines and associated lymph nodes) must undergo visual inspection

and palpation. For this risk assessment PH, AH and AW risks associated with three scenarios have

been studied:

(i) current GO inspection regime;

(ii) only visual inspection; and

(iii) total absence of GO inspection.

The assessment aimed to produce a measure of the likelihood of a hazard to be present in a carcase

at chilling and to establish risk differences between the scenarios.

Data and supporting information necessary for this research were obtained from official databases,

official reports and scientific literature. Expert opinion was used to address information and data

gaps.

Conclusions

Effectiveness Assessment Tool

The results of the initial validation of the tool were satisfactory. It showed a good discrimination

capacity that allows for appropriate comparison of effectiveness among MI tasks. However, further

validation would confirm the suitability of the model for a greater number of hazards. The results so

far are promising and further work should be encouraged.

The assessment findings suggest that only 20 out of the 33 legally required MI tasks may be

contributing realistically to the detection of the hazards tested in this project. The outcomes on the

selected hazards were in line with the experts‟ expectations and experience.

A great constraint on the work was the lack of data and information to include in the model. It will

require a substantial amount of field-based research to obtain precise data.

Risk Assessment

The qualitative risk assessment for the three GO inspection scenarios showed that for the hazards

studied in this research – bTB, toxoplasmosis (in sheep), MAP, Salmonella (in pigs), CSF, hernia and

tail bites (in pigs) – the contribution of GO inspection was found to be of limited value because

lesions associated with these hazards are seldom manifested in GO alone or their detection is not

always followed by remedial action. Therefore, removal of this MI task would not make a substantial

difference to the detection of these hazards and to their consequent risks to PH, AH and AW.

Understanding the results

The findings of this research highlight the correlation between pathogens, animal health and welfare,

meat production and safety of food products. These relationships must be considered in order to

understand:

o which MI tasks have a significant impact on the protection of public health, animal health and

welfare.

o which MI tasks have a significant impact on the presence of hazards.

o whether the slaughterhouse is the best place to control certain PH, AH and AW risks.

The outputs of the project will help to assess the value of the current MI process and to identify areas

where improvements can be made to increase effectiveness while ensuring an appropriate level of

public health, animal health and welfare protection.

Section 3 : Achievements of Project Targets

SCIENTIFIC OBJECTIVES (from Scope of Work section SW1):

Objective 01

Create an inventory of hazards to human health, animal health and animal welfare related to

meat production and its related conditions. Identify available meat inspection tasks at the

slaughterhouse (including ante and post-mortem) for each of them.

Extensive literature review was conducted to identify all hazards (public health, animal health

and welfare) associated with meat production in the UK. Inspection data from FSA were also

consulted. Meat inspection practices at the slaughterhouse (as described in the relevant

European legislation) were mapped as well as their suitability to identify a selection of hazards

(the most relevant hazards). The focus of this review was on biological hazards; however, a

narrative review of chemical and physical hazards associated with meat production was also

carried out and it is included in the report.

Objective 02

Development of a qualitative approach to assess the relative effectiveness of inspection

activities. This will produce a scientifically valid assessment tool to evaluate effectiveness of

the various available meat inspection activities.

A computer based model has been developed that maps the meat inspection practices at the

slaughterhouse (ante and post-mortem). The model produces, by analysing numerical inputs

(sensitivity and positive predictive value), a qualitative score that indicates the inspection

task‟s capacity of detection of a specific hazard. It can be applied to public health, animal

health and animal welfare hazards.

For each hazard, the qualitative scores of the different tasks are comparable; the outcome can

be therefore understood as a “relative capacity of detection”.

Objective 03

Evaluate the suitability of each inspection task for a selection of hazards (for human health,

animal health and animal welfare).

The model has been applied to 7 hazards (3 for public health, 2 for animal health and 2 for

animal welfare). The model has been evaluated by different external experts involved in the

project and modified accordingly. Although initial validation has been achieved, the validation

should be expanded to include other hazards to make sure the model responds appropriately

to a great range of situations. A report on the activities undertaken as part of this objective

along with an electronic version of the model accompanies the final report.

Objective 04

Create a generic risk assessment model mapping all inspection tasks at the slaughterhouse.

Please refer to report N3 for information on the „risk pathway‟ assessment.

Objective 05

Qualitatively evaluate the level of risk for specific hazards associated with the current and

alternative green offal inspection activities.

Two modifications to the original proposal have been introduced. The pathway developed

under objective 4 was simplified in order to be used for objective 5. Specifically, for objective 5

we focused on activities that take place at the slaughterhouse (i.e. we did not evaluate risks at

the farm or during transport).

Secondly, the original proposal stated (objective 05. Task 02): “... the evaluation of the risk is

understood in this project as the probability of detecting the condition associated with a

specific hazard (...) and the consequences for public health, animal health and animal

welfare.” Our risk assessment evaluates the likelihood of a specific hazard being present at

the end of the slaughter line (e.g. chiller).

Instead of accurate measurement of consequences, we have made a general comment of

what implications will the presence of hazards in/on the carcase in the chilling room have for

public health, animal health and animal welfare. This has been done assuming that all

subsequent steps will not impact in the level of contamination of the carcase/meat.

Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA

Tel: +44 (0)1707 666333 Fax: +44 (0)1707 652090 Email: [email protected]

Project MC1003

Outcomes and values of current ante- and post-mortem meat inspection tasks

and

Assessment of benefit to public and animal health of post-mortem

inspection of green offal in red meat species at slaughter

Project Report N.1

Authors: Silvia Alonso, Lecturer in Veterinary Public Health

Nikolaos Dadios, Research Assistant

Neville Gregory, Professor in Animal Welfare Physiology

Katharina Stärk, Professor in Veterinary Public Health

Department of Veterinary Clinical Sciences, RVC

Project MC1003 2010

2 Outcomes and values of current ante- and post-mortem meat inspection tasks – Report 1

Outcomes and values of current ante- and post-mortem

meat inspection tasks

Project code: MC1003

PROJECT REPORT N.1 (Objective 1) – Inventory of hazards to human

health, animal health and animal welfare related to meat production and

its related conditions. Identify available meat inspection tasks at the

slaughterhouse for each of them.

SCOPE OF STUDY

This report outlines the activities conducted and results obtained as part of the first

objective of the project MC1003. The scope of this first objective was to create an

inventory of hazards to public health (PH), animal health (AH) and animal welfare

(AW) related to meat production and to assess the extent to which the current meat

inspection tasks at the slaughterhouse address those hazards. The project focus is on

red meat production, and specifically cattle, pig and small ruminants.

BACKGROUND

Meat inspection (MI), comprising ante- and post-mortem inspection, represents a

fundamental control point for the various hazards associated with the meat

production chain. It was established in the nineteenth century, when it was

discovered that some serious human diseases originated in food animals and could

be transmitted to humans through the consumption of meat (Edwards, Johnston et

al. 1997). The aim of such inspection was to prevent transmission of infectious agents

from animals to humans by detecting sick animals or infected carcases and

preventing them from reaching the consumer. The underlying principle was that

animal diseases presented with macroscopic lesions in specific organs of the animal

and those were easily identifiable during carcase inspection (Pointon, Hamilton et al.

2000). Identification of such lesions was followed by appropriate measures to stop

Project MC1003 2010


those animals or parts of the animals to get to the subsequent steps in the food chain

(Edwards, Johnston et al. 1997). Meat inspection practices have not changed much

since its inception and still rely heavily on the detection of macroscopic signs and

lesions in organs and carcases (Reg. (EC) 854/2004). In addition, it appears to be a

rigid and very prescriptive inspection (Gracey, Collins et al. 1999). It has been

transposed and use in areas and countries of great geographical distance, where

farming methods and animal diseases were very different to those in Europe

(Hathaway 1993).

Later, meat inspection practices started playing an increasingly important role in

protection of animal health and welfare. Inspection at the slaughterhouse is one of

the most suitable points along the food chain to collect a variety of data that can be

used not only for early identification of epidemics or emerging diseases but also to

guide the formulation of future policies regarding animal health on the national herd

(Gracey, Collins et al. 1999; Garcia, Gonzalez et al. 2003). Nevertheless, the primary

role of MI is still nowadays the protection of public health.

It is well recognized that the traditional meat inspection has accomplished a very

important role in protecting the public from meatborne zoonoses. Many diseases that

not very long ago were ravaging human health have now reduced their incidences,

and in some cases virtually disappeared from the main part of the European

continent (Edwards, Johnston et al. 1997). Illnesses that were affecting big parts of the

human population are now been seen only sporadically and are many times

imported from other countries. This is especially common with parasitic diseases that

are connected to unsanitary conditions in the human population and low meat

inspection standards (Sciutto, Fragoso et al. 2000; Garcia, Gonzalez et al. 2003).

Although meat inspection at the point of slaughter was only one part of a broader

process, it is well accepted that it represents an important one (Garcia, Gonzalez et al.

2003).

Despite the success of MI to contain major human health hazards, today new

threats seem to have become more prevalent. These new hazards, helped by the

modern, industrialised way of food processing and distribution, and the increased

mobility across the globe of a big part of the human population, can reach a greater

number of people and have very serious consequences. Examples are spongiform

encephalopathy agents, campylobacter, drugs residues and chemical contaminants.

While some of these hazards may cause clinical disease on the animal host, many

exist subclinically. As a result it is currently questioned to what extent the traditional

inspection practices are suitable to deal with these hazards (Pointon, Hamilton et al.

2000). Even more, experts have suggested that traditional meat inspection may

contribute to the spread of these agents (Edwards, Johnston et al. 1997; Pointon,

Hamilton et al. 2000).

Project MC1003 2010


Policy makers and stakeholders suggest the traditional meat inspection system at

the slaughterhouse is not fit anymore to protect the public against these diseases and

a radical overhaul and a new way of thinking is necessary (Edwards, Johnston et al.

1997; Mousing, Kyrval et al. 1997; Gracey, Collins et al. 1999; Pointon, Hamilton et al.

2000). The argument is based on the fact that, the diseases identifiable in traditional

MI rarely present a risk for the consumer. The real risk currently lies with the

invisible hazards(Mousing, Kyrval et al. 1997).

In order to evaluate the suitability of the current meat inspection practices to

protect public and animal health and animal welfare, risk assessment principles

should be applied in the identification and assessment of hazards, to make the most

effective use of limited existing resources (Pointon, Hamilton et al. 2000). A holistic,

or “farm to fork”, approach should be taken, that will focus on the most critical steps

in the identification of hazards from the farm till the final product (Desmarchelier,

Higgs et al. 1999).

The first part of this project, outlined in this first report, examines the extent to which

the most common meatborne hazards are suitable of being identified via the

traditional MI practices as outlined in Regulation (EC) 854/2004. The evaluation

includes public health, animal health and animal welfare hazards. A comprehensive

list of hazards is created, followed by a process of selection of those particularly

relevant to the meat production. In a second step, the tasks that a meat inspector is

legally required to carry out at the slaughterhouse are listed and then matched to

each of the hazards they are suitable to identify.

TYPES OF HAZARDS

The project looked at biological, chemical and physical hazards. Nevertheless, on the

bases of (a) the actual relevance for either animal and public health and animal

welfare and (b) the capacity of current meat inspection tasks, based primarily in

visual inspection, palpation and incision, to identify each of these types of hazards,

the research work presented in this report focuses primarily in biological hazards.

Some considerations in relation to physical and chemical hazards are provided in the

discussion session of this report.

Project MC1003 2010


MATERIALS AND METHOD

Task 1. Inventory of hazards to public health (PH), animal health (AH) and animal

welfare (AW) related to meat production

For the scope of this first objective a comprehensive list of hazards associated with

meat production was compiled. Specifically, our review consisted in two parts: (i)

identification of hazards related to food production/consumption; (ii) selection of

hazards relevant to the scope of our project. In the context of this project, hazards

means any physical, chemical or biological agent that may cause any type of public health,

animal health and animal welfare risk. The review focuses in the UK and whenever

relevant, in the EU.

This first task is divided in the following two steps:

Step 1.1. Comprehensive list of hazards

(PH) – As a point of departure, a comprehensive list of public health hazards

was created by collating information on all types of public health hazards

(ever) associated with consumption of food. The list includes all those hazards

that were reported in literature as being related to food consumption

(including vegetables and waterborne hazards). Three main sources of

information were used to collect information about foodborne related hazards:

(i) the scientific literature, (ii) reports from official organizations (FSA, EFSA,

OIE, DEFRA, HPA), and (iii) data from these and other relevant organizations.

A comprehensive table was created collating information from all the sources

above. The table includes information for each identified hazard such as name

of pathogen, host animal species, degree of its association to foodborne

poisoning, food vehicles, incidence in humans, features of the clinical

presentation, degree of its association to red meat, prevalence of the hazard in

live animals and prevalence in carcase meat, among others.

(AH) - The list of Notifiable Animal Diseases as published by the OIE

(http://www.oie.int/eng/maladies/en_classification2010.htm) was used as the

reference list for Animal Health hazards. This is understood as the most

comprehensive list of hazards of interest to Great Britain. The diseases

relevant to cattle, small ruminant and/or pigs were extracted from the list.

Project MC1003 2010


(AW) – Information was obtained via expert elicitation. An initial list of

potential animal welfare hazards1 for each of the target species was created by

initial consultation with 3 veterinarians with expertise in animal welfare.

Subsequently a questionnaire was created and distributed online among

Official Veterinarians and Meat Inspectors to collect their views on the

frequency and importance of each of the listed AW hazards (see annex 1).

Participants in the survey were asked to rate (1 to 5, from low to high) each AW

hazard according to the frequency of observation in their abattoirs. Secondly,

the survey required the participants to rate (1 to 4, irrelevant to extremely

important) each AW condition according to the perceived importance/severity

in the individual animal and on an average affected animal (i.e. not the

extreme cases). Baseline information about the participants and their plants

was also collected.

Step 1.2. Selection of hazards relevant to the scope of our project

(PH) - A decision tree is used to create a scrutinized list that includes the most

relevant hazards to meat production from those identified in step 1. See

Annex 2 for an outline of the selection tree. Information to inform the

inclusion/exclusion process is obtained from various sources, including

scientific literature and official reports from various relevant organizations.

(AH) – A selection tree was produced to scrutinize the comprehensive list and

focus the subsequent work in those hazards that are more relevant to the

current situation in Great Britain. The selection tree is outline in Annex 3. The

information to inform the inclusion/exclusion process was obtained from

official reports and published information in the websites of DEFRA and

DARD

(http://www.defra.gov.uk/foodfarm/farmanimal/diseases/atoz/notifiable.htm;

http://www.dardni.gov.uk/index/publications/pubs-dard-animal-

health/publications-ahw-notifiable-diseases.htm).

(AW) – The outcomes from the survey were summarized. A score for

frequency and score for relevance was obtained by pulling all the rating given

by all respondents to each AW hazard. Specifically the “score” corresponds to

the median2 of the values entered by the participants. The median scores for

1 In this project “animal welfare hazards” refers to “animal welfare conditions”. For consistency

throughout the report the first term will be used. 2 The value that separates the higher half of the scores from the lower half

Project MC1003 2010


severity and frequency were cross-tabulated in order to map the relative

importance (frequency*severity) of each AW hazard. Hazards were selected

according to this relative importance; very frequent hazards (score 4-5) were

selected, regardless of their relevance for AW. Very severe hazards (score 4)

were selected regardless of their frequency.

Task 2. Identification of conditions/lesions related to each hazard

The clinical picture associated with each selected hazard was described. Information

was collected from the scientific literature. Data derived from meat inspection in

Great Britain was used to get an understanding of the common features found in

slaughterhouses over the last years. Although this list is not meant to be a precise

reflection of the frequency with which each lesion is found, it was used as a proxy for

the likelihood of each lesion to be identified at slaughter.

Task 2 applies only for AH and PH hazards as, in the context of this project, AW

hazards are lesions/conditions per se.

Task 3. Identification of meat inspection practices pairing to hazards

The list of the current meat inspection practices is obtained from the relevant

legislation, namely Reg. (EC) 854/2004. For each of the hazards created under task 1

(step 1.2) we created a list of inspection practices that have the potential to be

detected current inspection practices. Information from three main sources was used

to undertake this task: scientific literature, official reports and the outcomes from

meat inspection in the UK in the past years (source: FSA)

The following report of results is divided into three sections:

• Section A: public health hazards (PH)

• Section B: animal health hazards (AH)

• Section C: animal welfare hazards (AW).

Project MC1003 2010


RESULTS

Section A: public health hazards (PH)

Task 1. Comprehensive list of foodborne hazards

A comprehensive list of foodborne hazards was created. A total of 46 foodborne

biological hazards were identified, including bacteria, virus and parasites (table 1).

Multiple sources of information were consulted. Relevant information to undertake

this task was obtained from a variety of sources (see bibliography). Literature was

scarce and in some cases contrasting. The list includes few hazards (viruses) which

are not known to be zoonotic; but most of the identified hazards have at least one

species of animals as reservoir. We adopted a conservative approach so as to create

the broadest possible view of public health hazards. The information available for

each hazard was also very variable. A summary of the information collected is

available as an electronic file (hazards comprehensive list.xls). The comprehensive list of

hazards was subsequently revised to produce a more concise list including public

health hazards of interest to our project. We produced a list of sixteen (16) meatborne

biological hazards that can be considered the ones of major significance to the GB

context (highlighted in table 1) (annex 4).

Task 2. Identification of lesions associated with each hazard

For each hazard a list of possible clinical conditions was compiled. The literature,

grey and scientific, was consulted to ensure the broadest range of conditions is

captured. For reference, data obtained from the Food Standards Agency relative to

outcomes of the meat inspection practices in Great Britain was used to get an

appreciation of the extent to which those conditions are presented at the

slaughterhouse. This data was not considered to be of high accuracy, as it was not

possible to assess the sensitivity and specificity of the inspection and the reporting

system. For these reasons the data were used only to confirm the findings from the

literature. A complete list of hazards with its associated clinical presentation and

inspection findings is provided in Annex 5.

Project MC1003 2010


Task 3. Pairing inspection practices and hazards

The list of meat inspection practices as specified in EC legislation was compiled.

Inspection practices are divided in Reg. (EC) 854/2004 in obligatory (i.e. to be

undertaken for each slaughtered animal) and optional (i.e. at the discretion of the

Official Veterinarian). Only obligatory inspection practices were considered in our

study as this are the only tasks expected to be conducted systematically at slaughter.

Each selected hazard and the lesions that are potentially visible at slaughter were

paired against each inspection practice. This was done for the three species under

study (cattle, sheep and pigs). Given the size of the document, details are provided in

an electronic file (hazards-meat inspection tasks.xls).

Table 1. Comprehensive list of foodborne pathogens

BACTERIA PARASITES and protozoa VIRUS, Rickettsia and Prions

Campylobacter spp * Trichinella spp * TSEs / vCJD *

Salmonella spp * Teania saginata (C. bovis) * Adenoviridae

Yersinia spp * Taenia solium (C. cellulosae) * Anthrax

VTEC * Echinococcus (hydatidosis) *1 Astrovirus

Mycobacterium bovis * Sarcocystis suihominis * Enterovirus

Mycobacterium avium subsp.

paratuberculosis *

Sarcocystis hominis * Norovirus

Streptococcus suis * Toxoplasma gondii * Rotavirus

Staphylococcus aureus Fasciola hepatica *1 Sapporo-like virus

Bacillus cereus Giardia spp Flavivirus

Arcobacter spp Cryptosporidium spp Hepatitis A

Aeromonas spp Balantidium coli Coxiella burnetii (Q-fever)

Shigella Isospora belli

Brucella spp Capillaria hepatica

Vibrio cholerae

Listeria monocytogenes

Clostridium botulinum

Erysipelothrix rhusiopathiae

Clostridium perfringens

Streptococcus spp

Francisella tularensis (Tularaemia)

*Hazards that passed the inclusion/exclusion criteria. 1

Hazards not meatborne related but for which meat is an essential components of transmission.

Project MC1003 2010


Section B: animal health hazards (AH)

Task 1. Comprehensive list of animal health hazards

A total of forty-four (44) diseases were identified for cattle, small ruminants and pigs

from the list of notifiable diseases published by the OIE. The list of identified

“hazards” is provided in table 2. A decision tree was created to narrow down the list

to include those particularly relevant to the aims of this project. Inclusion/exclusion

criteria include:

i. Included in the list of Notifiable diseases in GB.

ii. Reported in the country in the last 10 year (2000-2010)

The inclusion/exclusion process (annex 3) was followed. This produced a final total

of nine (9) diseases (highlighted in table 2).

Task 2. Lesions associated with each hazard

The clinical presentation and the potential lesions suitable to be identified during

slaughter were collected for each of the identified AH hazards. We excluded those

pathogens (n=3) that had been covered in Section A (public health hazards), as the

information had already been collected. The literature, grey and scientific, was

consulted to ensure the broadest range of conditions was captured. For reference,

data obtained from the Food Standards Agency relative to outcomes of the meat

inspection practices in Great Britain was used to get an appreciation of the extent to

which those conditions are presented at the slaughterhouse. A complete list of

hazards with its associated clinical presentation and inspection findings is provided

in Annex 6.

Task 3. Pairing inspection practices and hazards

The list of meat inspection practices outlined in Reg. (EC) 854/2004 was matched to

the lesions associated with each animal health hazard. Only obligatory inspection

practices were considered. Each selected hazard and the lesions that are potentially

visible at slaughter were paired against each inspection practice. This was done for

Project MC1003 2010


the three species under study (cattle, sheep and pigs). Details are provided in an

electronic file (animal health hazards-meat inspection tasks.xls).

Table 2. Comprehensive list of animal health hazards

BACTERIA PARASITES and protozoa VIRUS, Rickettsia and Prions

Brucella abortus* Echinococcosis Anthrax*

Bovine Tuberculosis* Trypanosoma evansi Foot and Mouth Disease

Virus*

Enzootic abortion Trichinellosis Bluetongue*

Brucella melitensis Theileriosis Scrapie*

Brucella suis Porcine cysticercosis Classical Swine Fever*

Paratuberculosis BSE*

Tularemia Aujeszky’s disease*

Q fever Bovine Viral Diarrhea

Chimean Congo Haemorrhagic

Fever

Infectious Bovine

Rhinotracheitis

Contagious pleuropneumonia Maedi-visna

Contagious agalactia Heartwater

Salmonella abortusovis Rift Valley Fever

Bovine anaplasmosis Rinderpest

Bovine babesiosis Vesicular stomatitis

Bovine genital campylobacteriosis Peste des petits ruminants

Leptospirosis Sheep and goat pox

Enzootic bovine leukosis

Haemorrhagic septicaemia

Lumpy skin disease

African swine fever

Nipah virus encephalitis

PRRS

Swine vesicular disease

Transmissible gastroenteritis

*Hazards that passed the inclusion/exclusion criteria.

Project MC1003 2010


Section B: animal welfare hazards (AW)

Task 1. Comprehensive list of AW hazards

An initial meeting with experts produced a list of 13 AW conditions in cattle, 18 AW

conditions in small ruminants and 8 AW conditions in pigs (table 3). This list of

conditions for the various animal species formed the basis for the “expert survey”.

The survey was circulated among a restricted number of lead veterinarians with

instructions to circulate among OV and MI in their respective clusters. It is not

possible to know the total number of veterinarians who received the online

questionnaire, as it is likely the email was further circulated among OVs and MIs

upon reception. At 17 October 20103, the survey had 101 responses which were used

for our project. Nine (9) responses were not valid as the questionnaire had not been

completed.

The participation was considered good. Most of the participants were either OV (62)

or MI (22). The remaining 8 participants fell out of these categories, and included

lead veterinarians, technical staff and academics working in the area of veterinary

public health. The number of years of experience in the meat industry was very

variable, ranging from 2 years to 49 years (median = 7). The experience across species

was variable. Eighty two (82) respondents worked in cattle plants, eighty-one (81) in

small ruminants and sixty-four (64) in pig plants. The survey did not contribute to

expanding the list of initially identified AW hazards as few respondents added extra

conditions.

Participants ranked each condition (see materials and methods) according to

frequency and severity. Almost all conditions were retained by participants to be of

medium to high animal welfare importance. The frequency of presentation of those

conditions at slaughter was varied, covering very rare to very common conditions

(see table 4). As a result, cross-tabulation left only few hazards out of our range of

interest. The selected AW hazards are presented in table 5.

3 At the time of finalising this report (29 October 2010) the online survey had reached approx. 118

responses.

Project MC1003 2010


Task 3. Paired AH hazards with inspection practices

The list of AW hazards (“conditions”) was matched with the current meat inspection

practices at the slaughterhouse to identify those hazards for which a suitable

inspection practice is not available. Results are provided as an electronic file (animal

welfare hazards-meat inspection tasks.xls).

Table 3. Comprehensive list of animal health hazards

CATTLE SHEEP PIGS

Legs fractures Bruising Tail bites

Luxation/split hip Dog bites Fighting wounds

Broken horns Pneumonia Hit marks

Rumenitis/ Gastritis / Haemorrhages in

stomachs

Ruminitis/Gastritis/Haemorrhages in

stomachs

Fractures/joint

luxations

Foot and leg conditions (inc arthritis) Foot and leg conditions (exc. fracture) Arthritis

Emaciation Emaciation Gastric ulcers

Mastitis Mastitis Immobile/weak/split

legs

Bruising Luxation / Fracture

Weakness/immobility Broken horns

Eye conditions Weakness / immobility

Tumours Eye conditions

Lungworm/lung diseases Tumours

Arthritis

Lungworm

Infected/rotten wounds

Fresh wounds

Fly strike

Acute scab

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Table 4. Median score for severity and frequency for each AW hazard, by species

CATTLE

CODE Condition

Frequency

median

Severity

median

BR Bruising 4 3

LW Lungworm 4* 2

FL Foot/leg cond. 3 3

MA Mastitis 2 3

EY Eye cond. 3 2

EM Emaciation 2 3

BH Broken horns 2 3

WI Weakness/immobility 2 3

TU Tumours 2 2

RG Rumenitis/gastritis 2 3

LU Luxation 2 4

LE Leg fractures 1 4

SMALL RUMINANTS

CODE Condition

Frequency

median

Severity

median

LW Lungworm 5 2

PN Pneumonia 5 2

FL Foot/leg cond. 4 3

AR Arthritis 4 4*

BR Bruising 3 3

EM Emaciation 3 3

EY Eye cond. 3 2

MA Mastitis 2 3

WI Weakness/immobility 2 3

BH Broken horns 2 3

IW Infected/rotten wounds 2 4**

FW Fresh wounds 2 3

TU Tumours 2 2

RG Rumenitis/gastritis 2 3

LF Luxation/fracture 2 4

FS Fly strike 2 3

DB Dog bites 1 3

AS Acute scab 1 3

PIGS

CODE Condition

Frequency

median

Severity

median

FW Fighting wounds 4 3

TB Tail bites 4 3

AR Arthritis 4 3

HM Hit marks 2 3

LF Fractures/luxation 2 4

WI Immobile/weak 2 4

GU Gastric ulcers 2 2

*data not available - extrapolated from pigs

** rounded up from 3.5

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Table 5. Relative importance scoring (yellow cells = selected hazards)

CATTLE - Ranking on medians

Frequency

1 2 3 4 5

Severity 1

2 TU EY LW

3 MA, EM, BH, WI, RG FL BR

4 LE LU

SMALL RUMINANTS - Ranking on medians

Frequency

1 2 3 4 5

Severity 1

2 TU EY LW, PN

3 DB, AS

MA, WI, BH, FW, RG, FS BR, EM FL,

4 IW, LF AR

PIGS - Ranking on medians

Frequency

1 2 3 4 5

Severity 1

2 GU

3 HM FW, TB, AR

4 WI, LF

Project MC1003 2010


DISCUSSION

This report provides an overview of the most important animal health, public health

and animal welfare hazards that are relevant to the red meat industry, and

specifically to GB. The project has aimed at providing a comprehensive revision of

hazards, followed by more in depth investigation of selected ones that are likely to be

more relevant for this country (in terms of actual burden of either human health,

animal health and animal welfare).

The project has combined a range of methods to reach a broad spectrum of

information sources. The scientific literature on this topic has been found to be

lacking to a great extent or, in many cases, outdated. This report therefore

summarizes the best available evidence to date. Whenever published sources of

information were totally lacking, expert consultation has been undertaken. This is

suggested as the most reliable source in the absence of more formal sources. In the

context of this project, this source has been key to ensure completion of the activities

planned for this first objective.

In the tables provided as part of this report (...hazards-meat inspection practices.xls) it is

possible to visualize which are the inspection practices that are suited to identify

specific hazards. It can be seen that, for some of the hazards (e.g. gastrointestinal

microorganisms) the current meat inspection practices only allow to detect specific

forms of the disease. These clinical signs are though not present in all infected

animals, what reduces the absolute efficacy of the practice to detect that hazard. It

has to be noted that the results of this first objective aim at giving a general overview

of the degree to which current practices match the clinical presentations of the most

important hazards. This report therefore does not provide an evaluation of the “real

value” of specific inspection practices to protect public health, animal health and/or

animal welfare, as this will depend, among others, on the frequency with which

specific clinical signs appear in association with specific hazards.

By the results of our lesions-inspection tasks pairing exercise, it seems that all

inspection practices effectively target at least one hazard. In most cases they are

Project MC1003 2010


suited to identify more than one hazard, but this seems again to depend on the

frequency of appearance of clinical signs in infected animals. Nevertheless, the

exercise highlighted a few inspection tasks for which there were no grounds to

believe they were suited to identify any of the considered hazard. For example, when

looking at the most relevant public health hazards, the following inspection tasks did

not seem to be able to target any: AM inspection; pleura, peritoneum and joints

inspection; pericardium and renal LNs; head, retropharyngeal LNs, submaxillary

LNs and parotid LNs. Ultimately this seems to be conditioned by the extent to which

that hazard will present with the expected clinical signs.

However, some of the above outlined inspection tasks, especially AM inspection and

inspection of the head, showed to be very important in the identification of animal

health hazards, as well as almost all animal welfare hazards. Not surprisingly, AM

inspection seem to be the only task able to ensure appropriate identification of a

greater range of AW conditions. For some of those conditions, AM inspection is the

only suitable meat inspection practice.

The first objective of project MC1003, presented in this report, aimed at providing a

easy to read and general assessment of the matching between specific hazards and

official inspection practices. The information used to inform the process for this

objective is relative to the current situation in GB. Although it is likely that most of

the reported findings will apply similarly to other EU Member States, this cannot be

assumed without appropriate evaluation.

Finally, the authors of this report would like to emphasize that the findings of this

report do not represent an accurate assessment of the level of public health, animal

health and animal welfare protection provided by the current meat inspection tasks.

To make such an evaluation, a formal socio-economic analysis should be undertaken

covering the potential economic impact to industry, society and other stakeholders;

an assessment on public and animal protection from food derived risks and

consumer attitudes towards a different meat inspection system.

Project MC1003 2010


Considerations on physical and chemical hazards

Physical hazards

After reviewing the literature on meatborne hazards, and taking into account the

number of articles dedicated to each category of hazards (biological, chemical and

physical) the conclusion is drawn that the risk of physical hazards related to the meat

production is relatively less relevant for AH, AW and PH. Moreover, physical

hazards relate only to public health - We could not find any meatborne physical

hazard of importance for AH or AW.

The existing literature on physical hazards is very limited. The only two physical

hazards identified through literature that can originate in animals are (i) broken

needles, or fragments of needles, that are used for veterinary purposes (vaccinations

and injections of medicinal or similar products) and (ii) fragments of bullets, pellets

or similar projectiles that are used for hunting (Horchner, 2006). In the context of

meat inspection of farmed animals, the broken or fragmented needles play the most

important role, although it has been reported that projectiles, probably more often

airgun pellets, can be found in the bodies of animals due to malicious acts of people

(Stier 2003). On the other hand, the presence of lead shots, bullets etc. in the carcases

of hunted game should be considered as normal and, accordingly, these findings

should be expected in animals killed by shooting.

Broken or fragmented needles embedded in the tissues of the animals can cause a

variety of reactions in the body, mainly in the muscles. These reactions are usually of

an inflammatory nature, probably due to the presence of bacteria on the needle or of

the nature of the injected substance itself. The reactions are usually referred to as

“injection-site lesions” and may be abscessation (Houser 2004), scar tissue formation,

callus formation or cyst formation (Beechinor, Buckley et al. 2001). For example, the

prevalence of injection-site lesions in particular muscles on beef carcases in the US

ranged from 2% (Roeber, Cannell et al. 2001) to 10% (George, Morgan et al. 1995) to

20% (Beechinor, Buckley et al. 2001). Similarly, in Canada, in 1999, 0.2% of whole beef

carcases were found with injection-site lesions (Van Donkersgoed, Jewison et al.

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2001). In conclusion, these lesions are quite widespread and common and they are

well known to the farming and meat industry. Because they result in economical loss

to the industry, mainly due to the trimming required and the subsequent weight loss

of the carcass, and because they pose a potential public health hazard, a considerable

amount of research has been carried out and literature is available, especially from

the United States, to address this issue and to find solutions to it. Suggested solutions

have been needle-free injection devices (Chase, Daniels et al. 2008), education of the

farmers(Roeber, Cannell et al. 2001) and good farming practices, whereby cases of

broken needles are recorded and brought to the attention of the abattoirs and

inspection authorities (Maunsell 2004; Horchner, Brett et al. 2006). In addition,

research has been carried out on the reasons why needles break and how to reduce

the incidence (Hoff and Sundberg 1999)

Because of the lack of literature to indicate otherwise, we consider the vast majority

of the injection-site lesions to be just the reaction of the body to the injection itself,

rather than the breakage of the needle. This is also supported by George et al, 1995,

where during a histological examination of 15,464 injection-site lesions on a beef

muscle at boning room level, no broken needle or fragment was mentioned. It is very

difficult to quantify what proportion of injection-site lesions is caused by broken

needles but, taking the previous study into account we have to assume that it is a

very small proportion. This conclusion is supported by the fact that there are no

reports available on findings of needles in carcases during any kind of meat

inspection on the line or, at a later stage, during metal foreign bodies’ detection of cut

meat in the boning room. In a study carried out by Edwards and Stringer on foreign

matter contamination of food in the UK, 2,347 incidents were reviewed (of which 200,

or 8.8% meat or meat products) and needles did not appear at all in the list (Edwards

2007)

The value of post-mortem meat inspection in the detection of broken needles is

questionable and debateable. Most authors consider the most important stage of

preventing broken needles reaching the consumer to lay in the primary production.

That means that the frequency of breakage has to be reduced, either by applying

better injection techniques, by using better needles, by preferring SC rather than IM

injections (Hoff and Sundberg 1999), by the elimination of injections with needles

altogether (Chase, Daniels et al. 2008) or by the proper recording of broken needles

and warning of the parties further down the chain. Visual PM inspection is

considered by some authors as not adding any value (Horchner, Brett et al. 2006)

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while others believe it is a useful tool, and certainly one part of the whole control

process that should be in place for the detection of broken needles. (Houser 2004)

The authors of this study believe that PM MI has certainly a role to play in the issue

of broken needles in carcase meat. Despite that fact that, under realistic inspection

conditions (line speed, light levels etc.), it would be highly unlikely for a needle to be

detected during visual inspection, we nevertheless believe that the lesions caused by

the reaction of the body to the presence of a needle are extremely visible and easily

detectable. This opinion is supported by the high level of abscessation found in

common injection/vaccination sites during PM MI, especially on older animals. These

lesions are at the moment removed by the inspectors and, therefore, maybe one of

the reasons why not more needles are found in the boning rooms, or in the plates of

the final consumer, is exactly this inspection point.

Chemical hazards

The fear of food contaminated with various chemicals that may cause serious disease

to the consumer has always been widespread in the human population. At some

points in time, especially after the Second World War, the fear of residues in the food

ranked higher than that of microbiological contamination and disease. This may have

to do with the fact that microbiological agents normally cause obvious and acute

disease that, in addition, it is quite common among the population and every person

has had or will have experience with this kind of disease at least once in his lifetime.

Chemical contaminants on the other hand elicit a different kind of reaction. The

conditions they cause to humans are usually long term and insidious (Sharpe and

Livesey 2006). In addition, the perception is that they cause terrible conditions,

ranging from cancer to sterility to teratogenicity and hormonal imbalances. The

many food scandals that have occurred over time in the media have not helped to

abate this perception (Larsson, Olsson et al. 2005). Considering the numbers of

bacterial food poisoning that affect the human population and comparing them with

the incidence of chemical hazards in the same population, it seems hard to justify this

fear.

Chemical contaminants in food are a very wide group of substances. They range

from substances that are normally in use in agriculture, like veterinary medicines

Project MC1003 2010


and feed additives, pesticides (a group of chemicals that includes insecticides,

rodenticides and herbicides) and chemicals used in the maintenance of agricultural

equipment and buildings (engine oils and fuels, wood treatment preparations etc.) to

substances that are not in use, or should not be used, in agriculture and are not

normally expected to be found in agricultural products, including meat

(Waltnertoews and Mcewen 1994). The second category includes environmental

contaminants, like heavy metals (although some of them are also in use in

agricultural products, like arsenic in insecticides) (Sharpe and Livesey 2006; Andree,

Jira et al. 2010) and not licensed veterinary preparations (Reig and Toldra 2008), but

also substances, and especially heavy metal, found normally in soil in some cases

(Sharpe and Livesey 2006)

Each one of these chemicals can find its way, by accident or deliberate, to the body of

the farm animals and from there to the final consumer. Each one of them, depending

on the amount and the period of ingestion, has the potential to cause disease to both,

animals and consumers, and in this way may have an effect on animal health and

welfare, and also public health. In addition, most of these substances have the

capacity to bio-accumulate over time in the body of the animal, usually in the fat

tissue, with the result that the final consumer, being on the top of the food chain, can

receive in one go concentrations many times higher than the ones that the

contaminated animal would receive (Andree, Jira et al. 2010)

Because of the real risk these substances present to (mainly) PH, and because of the

perception of the public, the states have been forced to take action against these

contaminants. With regard to red meat, It must have been fairly obvious to the

legislators that the traditional MI system put in place in the abattoirs to deal mainly

with biological hazards was inadequate to deal with the chemical contaminants and

so other mechanisms and policies had to be put in place (Reig and Toldra 2008).

Nevertheless the existing MI system plays an important role in the fight against

chemical residues in meat and we will examine that role a bit later.

In this report we present the threat that chemical hazards pose to, primarily, the

public health and, secondarily, to animal health and welfare. Because of the vast

number of chemical groups, sub-groups and substances and the time limitations of

this project, this reports gives only a general overview of what these hazards are,

where they are found and how they can enter the food chain, what mechanisms are

Project MC1003 2010


right now in place to deal with them (on European level) and, finally, what the role

of the current meat inspection system is in all this. It should be noted here that toxins

produced by living organisms (plants, fungi etc.), although being able of entering the

food chain through animals and causing disease in humans, have been excluded

from this study.

The following pages provide a series of tables presenting relevant factual information

regarding chemical hazards (tables 6 and 7).

Control of chemical hazards

There are two main ways of protection of the public health against chemical hazards

originating from meat. The first is when there is an incident reported to the attention

of VLA. This will trigger an investigation and if the result of this investigation is

positive, the state will ask the farmer affected to voluntarily resist of sending the

contaminated animal(s) for slaughter, for a prescribed period. If the owner of the

animals will resist to this suggestion, the state can enforce this through the

Contaminants in Food (England) Regulations 2003.

The second way of control against chemical hazards in the food chain (including to a

great degree carcase meat) is through the regular monitoring of a variety of foods, as

prescribed in regulation (EEC) 2377/90. Through this regulation every member state

is obliged to implement a residues monitoring program and relay the information

back to the EU. Sampling is random and the substances to be tested are described in

the annexes of the above regulation. Annex I and III of that regulation include

veterinary medicines that are allowed to be used in farm animals, which are tested

against some limits (maximum residues limits, MRL). If a substance is found

exceeding the MRL, this is considered a positive result. Annex IV includes substances

that are not allowed for use in farm animals (phenylbutazone, growth promoting

hormones etc.) or are contaminants (heavy metals etc.) and, if found at any level, this

is considered as a positive result as well. All positive results have to be investigated

further to find, if possible, the reason of the problem.

It is obvious that by the time the results of the samples are back, the food in question

will have been consumed already and so this method is only retroactive and

preventive value

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Chemical Hazards and MI: Value of Meat Inspection

As presented in annex 7, all chemical hazards can cause obvious clinical disease and

most of them show pathological lesions. However, his happens normally in high or

very high exposure of the animals to the hazard, like during accidental ingestion of a

substance by an animal or group of animals. Most of the time the exposure is low

level and/or chronic and may not cause obvious signs. In addition, all of these signs

and PM findings are very similar to those caused by other diseases or conditions and

are therefore non-specific and not pathognomonic (Radostits and Done 2007). Taking

also into account the extremely low incidence of poisoning cases in the UK (VLA

2008), it would be overoptimistic to expect a veterinarian or an inspector to suspect,

let alone to diagnose, a chemical related condition in an animal.

Nevertheless, in our opinion the meat inspection at the abattoir can add some value,

based on the following points:

• Detain and sample suspect carcases (e.g. carcases with recent injection

lesions etc.). Diseased and abscessed animals have a higher probability to

have been treated with antibacterials and therefore test positive (“targeted

testing”). (Waltnertoews and Mcewen 1994)

• Check for signs of hormones or beta-agonists administration (extremely lean

carcases, carcases where the conformation does not match the age, gender

etc.)(Reig and Toldra 2008)

• Check for signs of implants in suspect sites: It is known that where hormones

and other preparations are used illegally, they are usually implanted in sites

like the base of the ear. A case like this could exhibit traces of the product

(boluses etc.) or reactive tissue (e.g. abscess, granuloma)(Gracey, Collins et al.

1999)

In all these cases the meat inspection could be a step in the whole chain of controls.

Some literature suggests that despite the large amounts of chemicals used in

agriculture, the residue levels in all foods have decreased in the past decades

(Waltnertoews and Mcewen 1994), (EFSA 2010). In addition, the effects of these

chemicals on the human body are in many cases not well understood, and it is

Project MC1003 2010


possible that the degree of harm is overestimated. Nevertheless, it is widely accepted

that most of the chemical hazards can, under the right circumstances, have a

detrimental effect on human health and therefore all efforts to monitor them and

keep them under control seem justified.

Table 6. Origin of chemical hazards

A. Man made B. Environment Combination of A and B

1. Veterinary medicines

2. Animal feed additives

3. Pesticides (especially the

ones applied to plants)

- Insecticides

- Herbicides

- Fungicides

4. Industrial products

- Batteries

- Paints

- Wood treatment

chemicals

- Lubricants

- Fuels

Industrial by-products

1. Plant toxins/metabolites

2. Fungal toxins

3. Animals’ own hormones

4. Soil / Water ingredients

(e.g. fluorine)

1. Minerals / (Heavy) Metals

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Table 7. Description of hazards in the food chain (animal—meat—consumer)

1. Naturally occurring

minerals

2. Pesticides / Insecticides

3. Herbicides

1. Additives

2. Plant toxins. Fungal toxins

3. Industrial (by-) products

1. Veterinary medicines

2. Animals own

hormones/metabolites

etc.

ENVIRONMENT

ANIMAL FEED

ANIMAL

MEAT

CONSUMER

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Project MC1003 2010


Annex 1. Online survey – Animal Welfare

ANIMAL WELFARE QUESTIONNAIRE4

1. BACKGROUND. INTRODUCTION

2. GENERAL DETAILS ABOUT PARTICIPANT

i. What is the current role (OV/MI/Other)

ii. Number of years working as Meat Inspector

iii. Gender (M/F)

iv. Species slaughtered in participants plant (Cattle/Sheep/Pigs)

v. Weekly throughput of animals slaughtered (for all species)

vi. Cluster where participant works (answer optional)

3. FREQUENCY OF ANIMAL WELFARE CONDITIONS* - (Cattle/Sheep/Pigs)

i. Never (i.e. less than once every six months)

ii. Rarely (i.e. once every six months)

iii. Often (i.e. once every month)

iv. Very often (i.e. several times per month)

v. Every day

4. RELEVANCE OF ANIMAL WELFARE CONDITIONS (SEVERITY)* -

(Cattle/Sheep/Pigs)

i. Irrelevant

ii. Slightly important

iii. Very Important

iv. Extremely important

v. Don’t know

5. CLOSING

i. Comments (if any)

ii. Would participate in further research projects in this area?

4 http://www.surveymonkey.com/s/animal_welfare_conditions_abattoir

Project MC1003 2010


*CONDITIONS ASSESSED:

CATTLE SHEEP PIGS

Legs fractures Bruising Tail bites

Luxation/Split hip Dog bites Fighting wounds

Broken horns Pneumonia Hit marks

Rumenitis/Gastritis/

Haemorrhages in stomachs

Arthritis Gastric ulcers

Foot and leg conditions (incl.

arthritis)

Foot and leg conditions (excl.

fracture)

Arthritis

Emaciation Emaciation Joint luxations

Mastitis Mastitis Immobile/weak/split legs

Bruising Luxation/Fracture Other

Weakness/Immobility Broken horns

Eye conditions Weakness/Immobility

Tumours Eye conditions

Lungworm/Lung diseases Tumours

Other Rumenitis/Gastritis/

Haemorrhages in stomachs

Lungworm

Infected/Rotten wounds

Fresh wounds

Fly strike

Acute scab

Other

Project MC1003 2010


Annex 2. Inclusion/exclusion decision tree – Public Health hazards

Selection of hazards that

have been associated (even

anecdotic ally) with meat

consumption.

Selection of hazards that can

be found in animals (i.e.

excludes those hazards that

are related to environmental

contamination.

Selection of hazards that are

more likely to derived from

animal contamination (i.e.

excludes those hazards

where contamination is

likely to occur in stages of

production after slaughter.

Explanatory notes

Project MC1003 2010


Annex 3. Inclusion/exclusion decision tree- Animal Health hazards

NO

YES

NO

YES

NO

YES

DISEASE APPEARED IN

THE UK IN THE LAST 10

YEARS?

OIE LIST OF NOTIFIABLE

DISEASES

DEFRA’S LIST OF

NOTIFIABLE DISEASES

EXCLUDED

EXCLUDED

DISEASE SELECTED FOR

FURTHER WORK

EXCLUDED

Project MC1003 2010


Annex 4. Inclusion/exclusion process – Public Health hazards

Pathogen / Agent 1. Is it / could it

be meatborne?

2. Does it / could it

originate in animals?

3. Are animals the

ONLY or MAIN

source?

Included in

final list

Campylobacter spp Y Y Y Y

Salmonella spp Y Y Y Y

L. monocytogenes Y Y N

VTEC Y Y Y Y

E. coli, other Y Y N

C. perfringens Y Y N

C. botulinum Y Y N

Yersinia spp Y Y Y Y

Shigella spp

Vibrio cholerae N

Staph. aureus Y Y N

Bacillus cereus Y Y N

Arcobacter spp Y Y N

Aeromonas spp Y Y N

Mycobacteria causing TB Y Y Y Y

M. avium paratuberculosis (MAP) Y Y Y Y

Brucella spp N

Anthrax Y Y N

TSEs / vCJD Y Y Y Y

Typhoid / Paratyphoid fever

E. rhusiopathiae Y Y ?

Streptococcus suis Y Y Y Y

Project MC1003 2010


Streptococcus spp, others Y Y N

Coxiella burnetii N

F. tularensis Y Y

Y (but not C, S or

P)

Trichinella spp Y Y Y Y

Taenia saginata (C. bovis) Y Y Y Y

Taenia solium (C. cellulosae) Y Y Y Y

Echinococcosis* (Hydatidosis) N (but can be

detected during

MI)

Y Y Y

Sarcocystis spp Y Y Y Y

Toxoplasma gondii Y Y Y Y

Cryptosporidium spp Y Y N

Giardia spp N

Cyclospora cayetanensis

Balantidium coli N

Entamoeba histolytica N

Fasciola hepatica* N (but can be

detected during

MI)

Y Y Y

Hepatitis A N

Astrovirus N

Norovirus N

Enterovirus N

Rotavirus N

Adenoviridae N

Project MC1003 2010


Annex 5. Clinical presentation and inspection findings by hazard – Public Health hazards

CATTLE SHEEP PIGS Main references

HAZARD Clinical presentation Inspection Findings Clinical presentation Inspection Findings Clinical presentation Inspection Findings

Salmonella spp (S.

Typhimurium and S.

Enteritidis)

GENERALLY: Enteric

and/or Septicaemic

forms. Septicaemia

(calves). Acute

enteritis. Chronic

enteritis (usually

caecum and colon).

Fever, depression,

anorexia, abortion.

Septicaemia GENERALLY: Enteric

and/or Septicaemic

forms. Septicaemia

(lambs). Acute enteritis

(no chronic).

Enterocolitis. Fever,

depression, anorexia,

abortion.

Septicaemia GENERALLY: Enteric

and/or Septicaemic

forms. Septicaemia

(piglets). Acute

enteritis. Chronic

enteritis (usually

caecum and colon).

Septicaemia (Quinn 2002;

Radostits and

Done 2007)

Campylobacter

Mainly calves affected.

Diarrhoea (enteritis).

Dysentery. Abortion (by

C. jejuni).

NONE Gastroenteritis (lambs).

Abortion (C.jejuni)

NONE Colitis NONE (Quinn 2002;

Radostits and

Done 2007)

Y. Enterocolitica, Y.

pseudotuberculosis

Y.ps/tub: Clinical or

subclinical.

Abscessation in various

organs. Abortion.

Mastitis,

orchitis/epidydimitis.

Enteric and/or

septicaemic form.

Abortion.

Y.enterocolitica: usually

asymptomatic.

Enterocolitis

Enterocolitis,

mastitis, abscesses,

thickening of

intestinal wall

Y.ps.: Clinical or

subclinical.

Enterocolitis (after

weakening of the host

for other reasons),

abortion, mastitis,

lymphangitis,

abscesses.

Abscessation in various

organs. Abortion.

Mastitis,

orchitis/epidydimitis.

Enteric and/or

Septicaemic form.

Abortion.

Y.enterocolitica: usually

asymptomatic.

Enterocolitis

Enterocolitis, mastitis,

abscesses, thickening of

intestinal wall

Rarely/never clinical

disease. Enterocolitis.

Enteric and/or

Septicaemic form

Enterocolitis (Gracey, Collins et

al. 1999; Quinn

2002; Radostits

and Done 2007)

VTEC

Enterocolitis and

septicaemia in

newbornes

Enterocolitis and

septicaemia

(newbornes)

Enterocolitis and

septicaemia in

newbornes

Enterocolitis and septicaemia

(newbornes)

Enterocolitis and

septicaemia in

newbornes. Oedema

disease in weaners

Enterocolitis and

septicaemia

(newbornes).

Oedema

(Quinn 2002;

Radostits and

Done 2007)

Project MC1003 2010


TB

Chronic. Weight loss.

Coughing. Fever.

Respiratory and general

(loss of condition,

anorexia etc.) signs.

CNS (meningitis) signs.

Other signs depending

on affected organs

Tubercles and/or

inflammation in

almost any organ, but

mainly in lungs,

intestines and

corrresponding

lymphnodes

Respiratory and general

(loss of condition,

anorexia etc.) signs.

CNS (meningitis) signs.

Other signs depending

on affected organs

Tubercles usually

located in head LNs.

Generalisation not

common. Various,

general and not

specific signs. CNS

(meningitis) signs

(Gracey, Collins et

al. 1999; Quinn

2002)

M. avium subsp.

paratuberculosis

>2 years age. Chronic:

diarrhoea and

emaciation.

Lymphadenopathy

Intestinal wall

thicker. Mesenteric

LNs enlarged and

oedematous.

Thickened intestinal

wall. L/adenopathy

Chronic: diarrhoea and

emaciation. Disease in

sheep less marked.

Minimal findings. Intestinal

wall thickened.

Caseation/Mineralisation of

mesenteric LNs. Thickened

and oedematous mucosa,

mainly in ileus. Enlarged

lymphnodes and lymphatics

(cording)

(Quinn 2002;

Radostits and

Done 2007; Behr

and Collins 2010)

Streptococcus suis

Septicaemia and

associated signs

(arthritis, endocarditis

etc.) in pigs <3 months

old

Septic polyarthritis,

valvular

endocarditis,

bronchopneumonia.

(Quinn 2002;

Radostits and

Done 2007)

BSE

CNS signs (i.e.

behaviour and

locomotion

abnormalities).

Emaciation

Emaciation

(potentially)

(Gracey, Collins et

al. 1999)

Trichinella spiralis

Non specific:

Diarrhoea, fever,

muscular pain.

Younger pigs:

inappetance,

weakness

Usually no visible

lesions. Could

present with small,

greyish-white spots

in muscles.

(Taylor 1996)

T. saginata /

Cysticercus bovis

Usually no disease Cysticerci in muscles:

heart, tongue,

masseters etc.

(Taylor 1996)

T. solium / C.

cellulosae

Usually asymptomatic Cysticerci in

muscles. Later

stages, caseous or

calcified.

Predilection sites:

heart, diaphragm,

(Taylor 1996;

Sciutto, Fragoso

et al. 2000)

Project MC1003 2010


internal masseters,

tongue, neck,

shoulder, intercostal

and abdominal

muscles

Fasciola hepatica

Acute: metacercariae

migrating through liver

parenchyma: weakness,

anaemia, dullness etc.

Chronic: weight loss

Acute: necrosis of

liver, presence of

immature F.h. stages.

Chronic: emaciation,

anaemia, cholangitis,

liver fibrosis. Adult

parasites

Acute: metacercariae

migrating through liver

parenchyma: weakness,

anaemia, dullness etc.

Acute: necrosis of liver,

presence of immature F.h.

stages. Chronic: emaciation,

anaemia, cholangitis, liver

fibrosis. Adult parasites

(Radostits and

Done 2007)

Toxoplasma gondii

Mainly subclinical.

Young animals more

suscebtible. Abortions.

General, non specific

signs. All organs can be

affected.

Granulomata in all

organs (calcification

with time).

Predilection for CNS,

lungs, myocardium.

General findings:

l/adenopathy etc.

Mainly subclinical.

Young animals more

suscebtible. Abortions.

General, non specific

signs. All organs can be

affected.

Granulomata in all

organs(calcification with

time). Predilection for CNS,

lungs, myocardium. General

findings: l/adenopathy.

Mainly subclinical.

Young animals more

suscebtible.

Abortions. General,

non specific signs. All

organs can be

affected. Pigs are

easily infected but

rarely show clinical

disease

Granulomata in all

organs(calcification

with time).

Predilection for

CNS, lungs,

myocardium.

General findings:

l/adenopathy etc.

(Radostits and

Done 2007)

Sarcosystis spp

Vast majority of

infections with NO

clinical disease.

Abortions. Acute

disease: fever. Chronic:

emaciation, anaemia,

oesophagus problems.

Acute phase:

Weakness, fever,

abortion. Chronic:

weight loss, atrophy,

lethargy etc.

General: emaciation,

petechiae in many

organs, anaemia,

lymph/thy. Specific:

Myocarditis. Cysts.

S.hominis causes

microscopic cysts (i.e

not detectable). But,

it can cause myositis,

or no symptoms at

all. Cysts become

visible when

degeneration and

calcification.

Vast majority of

infections with NO

clinical disease.

Abortions. Acute

disease: fever. Chronic:

emaciation, anaemia,

oesophagus problems.

Neurological problems.

Acute phase:

Weakness, fever,

abortion. Chronic:

weight loss, atrophy,

lethargy etc.

General: emaciation,

petechiae in many organs,

anaemia, lymph/thy. Specific:

Myocarditis. Cysts.

Ecchymoses, petechiae,

hepatitis, glomerulitis,

encephalomyelitis

Vast majority of

infections with NO

clinical disease.

Abortions. Acute

disease: fever.

Chronic: emaciation,

anaemia, oesophagus

problems

General:

emaciation,

petechiae in many

organs, anaemia,

lymph/thy. Specific:

Myocarditis. Cysts.

In pigs S. cysts are

macroscopic. Can

cause also myositis

or no lesions at all

(Taylor 1996;

Fayer 2004;

Radostits and

Done 2007)

Echinococcus spp

No clinical disease (only

in extreme case not

specific signs)

Hydatid cysts, mainly

in lungs, followed by

the liver

No clinical disease (only

in extreme case not

specific signs)

Hydatid cysts, mainly in the

liver and the lungs

No clinical disease

(only in extreme case

not specific signs)

Hydatid cysts,

mainly in the liver

(Gracey, Collins et

al. 1999)

Project MC1003 2010


Annex 6. Clinical presentation and inspection findings by hazard – Animal Health hazards

CATTLE SHEEP PIGS Reference

HAZARD Clinical presentation Inspection Findings Clinical presentation Inspection Findings Clinical presentation Inspection Findings

Anthrax

Acute and severe

septicaemic disease

(fever, tremors,

dyspnoea, congested

and haemorrhagic

mucosae). CNS signs.

Diarrhoea. Oedema of

tongue, mouth, throat.

No rigor mortis. Blood

dark, not clotting.

Widespread septicaemic

signs (e.g. haemorrhages).

Characteristic: enlarged,

dark spleen ("blackberry

jam spleen"). Findings as

recorded in disease picture

(see cattle) (see cattle) General septiceamic disease

with characteristic oedema of

throat and face

(See cattle) Radostits, 9th

ed.

Foot and

mouth

disease

Fever. Salivation.

Lameness. Vesicles in

mouth and nasal

membranes, between

the claws and coronary

band and on the udder.

Anorexia. Shivering.

When complications:

tongue erosions,

mastitis, hoof

deformation.

Myocarditis. Abortions.

Weight loss

Vesicular/erosive

stomatitis and dermatitis

(e.g. feet, teats). Vesicles

and erosions in nasal

cavity, muzzle etc. Heart:

epicardial haemorrhages

with or without pale areas

(tiger heart). Tiger heart in

young animals

only/mainly. Erosions of

rumen pillars.

Fever. Salivation.

Lameness. Oral and

foot lesions (usually

mild). Agalactia.

Sudden death of

young animals without

signs

Vesicular/erosive

stomatitis and

dermatitis (feet, teats

etc.). Vesicles and

erosions in nasal

cavity, muzzle etc.

Heart: epicardial

haemorrhages with or

without pale areas

(tiger heart). Tiger

heart in young animals

only/mainly

Fever. Severe foot lesions, with

detachment of claw horn

possible. Vesicles on carpuses

(and other pressure points on

the limbs). Vesicles on snout

and tongue

Vesicular/erosive

stomatitis and

dermatitis (feet, teats

etc.). Erosions in nasal

cavity, snout.Heart:

epicardial

haemorrhages with or

without pale areas

(tiger heart). Tiger

heart in young animals

only/mainly

Radostits, 9th

ed. OIE –

technical

disease cards

Brucella

abortus

Mature animals.

Abortion. Fever (e.g.

depression).

Mastitis/orchitis and

arthritis/hygroma. Can

affect any organ

Necrotising placentitis.

Placenta with leather

appearance. Can affect any

organ(e.g.

vertebrae/discospondylitis,

endocarditis)

Radostits, 9th

ed. CSFPH –

Iowa State

Univ

Scrapie

CNS signs. Emaciation.

Pruritus

Emaciation. Signs

secondary to pruritus

(e.g. injuries, wool

loss)

Radostits, 9th

ed. Gracey,

1999.

Bluetongue

Fever. Erosions and

unceration in oral

cavity, lips.

(Mycopurulent) nasal

discharge. Facial

swelling. Usually

Mucosal and skin lesions

(as described above).

Generalised oedema and

haemorrhages.

Haemorrhage at base of

pulmonary artery.

Fever. Laminitis and

coronitis (lameness).

Dyspnoea, panting,

salivation, depression,

discharge/crust

around nostrils.

Mucosal and skin

lesions. Generalised

oedema and

haemorrhages.

Haemorrhage at base

of pulmonary artery.

Radostits, 9th

ed. CSFPH –

Iowa State

University.

(Office

Internationale

Project MC1003 2010


subclinical. Vesicular

ulcerative dermatitis.

Coronitis. Ulcers in the

mouth. Erosions and

crusts in nostrils.

Emaciation. Death or

long recovery with

alopecia and growth

delay

Muzzle, lips, ears

hyperaemic. Tongue

cyanotic (blue) and

swollen. Lips swollen.

Torticollis, vomiting,

conjuctivitis. Abortion.

Pneumonia.

Erosions and ulcers in

mouth cavity and

particularly on dental

pads. Hyperaemic

coronary bands. Nasal

and oral mucosa

cyanotic and necrotic.

Hyperaemia and

petechiae in many

organs (e.g. trachea,

heart). Hyperaemia

and erosions in

reticulum and

abomasum.

Haemorrhages and

necrosis on muscles

and fascial planes.

Broncholobular

pneumonia. Enlarged

lymphnodes and

spleen. Large amounts

of fluid in thoracic

cavity and pericardial

sac

des

epizooties)

Classical

Swine Fever

Viraemia signs (Acute form):

fever, depression etc. CNS

signs. Acute form: Anorexia,

lethargy, fever. Conjuctivitis.

Hyperaemic and haemorrhagic

lesions on skin. Cyanosis of

extremities. Dyspnoea, cough.

CNS signs (ataxia, paresis,

convulsions). Chronic form:

Dullness, pyrexia. Chronic

diarrhoea. Growth

retardation[3]. Congenital

form: Abortion. Foetal deaths,

mummifications.

Vireamia: diffuse

haemorrhages in

various organs.

Enlarged and

haemorrhagic LNs.

Petechiae in kidneys:

"Turkey egg kidneys". .

Necrotic foci in tonsils.

Characteristic lesions

in spleen (infarctions).

Lungs congested,

haemorrhagic.

CHRONIC: "Button"

ulcers in

intestine/colon.

Haemorrhagic and

inflammatory lesions

many times absent

Radostits, 9th

ed. OIE –

technical

disease cards

Project MC1003 2010


Annex 7. Clinical disease and post-mortem findings from chemical hazards

Table: CHEMICAL HAZARDS – Clinical disease and pathology findings

HAZARD CLINICAL Post mortem Source

Pb Neurological signs (acute), but

chronic poisoning also possible

(extended, low dose ingestion)[1].

Cattle: Acute/subacute: CNS signs

(convulsions etc). Sheep: paresis [2].

In all: acute gastroenteritis[2]

Liver and kidney degeneration

[2]. Gastroenteritis[2]

Sharpe,

2006[1].

Radostits, 9th

ed.[2]

As Gastroenteritis with diarrhoea and

dehydration. CNS signs (convulsions

etc.)[2]

Gastroenteritis[2]

Se Acute: dyspnoea, diarrhoea, death.

Chronic: emaciation, rough coat, stiff

gait, lameness[2]

Liver necrosis[2]

Fluorine Erosion of teeth. Lameness and

unthriftiness[2]

Osteofluorosis, osteoporosis.

Erosion of teeth[2]

Cu Sheep. Acute: GI tract mucosal

necrosis (diarrhoea, vomiting, shock).

Death. Chronic: haemolytic anaemia

(jaundice, haemoglobinuria[2]

Acute: Severe gastroenteritis.

Jaundice, sign of hemolysis

(swollen spleen, liver,

kidneys)[2]

Organochlorides

(DDT etc.)

CNS signs[2] -[2]

Organophosphates CATTLE. Acute: salivation, diarrhoea,

CNS signs. Delayed: CNS signs[2]

In acute: nothing. In delayed:

degeneration of peripheral

nerves and spinal cord[2]

Warfarin

(rodenticides)

Weakness, mucosal pallor, dyspnoea

etc.[2]

Massive internal bleedings[2]

Project MC1003 2010


Annex 8. Chemical/residues – public health implications

CHEMICAL

GROUP/Category

Chemical Possible effect/reaction to consumer References

Antibacterials

(antibiotics,

sulphonamides)

General - Allergic and other immunological reactions[1][6][8]

- Creation of resistant strains of bacteria[1][6][10]

- Direct toxicity [1][6][8]

- Antiparasitic drugs residues found less than antibacterials[1]

- Modification of indigenous human intestinal microflora[8]

- Poisoning cases are investigated as a result of direct request by the farmer/vet or in the

course of disease investigations[9]

- General belief is that risk to PH from a/b and a/p residues is minimal[1]

(Waltnertoews and

Mcewen 1994;

Waltnertoews and

Mcewen 1994;

Waltnertoews and

Mcewen 1994;

Waltnertoews and

Mcewen 1994;

Waltnertoews and

Mcewen 1994) [1-5]

Gracey, 1999[6].

Reig, 2008[8].

Sharpe, 2006[9].

(Gustafson and Bowen

1997)[10].

Andree, 2010[11].

(EFSA 2006; EFSA

2008; EFSA 2009) [12-

13]

Tetracyclines - Generally low toxicity/risk for PH at residue levels[1]

Beta-lactam

antibiotics

(Cephalosporins

etc.)

- Low toxicity but most common category causing allergic reactions (Canada)[1]

Chloramphenicol - Can cause serious reactions (aplastic anaemia, suppression of bone marrow folloewed

by leukaemia etc.)[1]

-

Sulphonamides - Can cause hypersensitivity and more serious reactions (effects on thyroid function,

aplastic anaemia etc.)[1]

Aminoglycosides

(streptomycin,

neomycin,

nitrofurans,

furizolidone etc.)

- Toxic to humans. In addition, mutagenic/carcinogenic (nitrofurans)[1]

Project MC1003 2010


Antiparasitic

drugs (e.g.

ivermectin,

closantel,

albendasole,

levamisole)

- Toxic. Carcinogenic/genotoxic (carbadox). Haematological abnormalities (levamisole)[1]

- General belief is that risk to PH from a/b and a/p residues is minimal[1]

Hormones –

naturally

occurring

Sex steroids

(testosterone,

oestradiol,

progesterone)

Somatotropin (ST,

or growth

hormone, GH)

- Varying amounts of these hormones are normally found in meat[2]

- Use: regulation of oestrous cycle (progesterone). Used to be used as growth promoters

in the 50’s-60’s (DES, diethylstilbestrol)[2]

- Some role in promoting growth of tumours, but not carcinogenic/genotoxic per se. No

toxic effects (at residue levels)[2]

- ST used for milk increase (cows) or growth promoter (pigs)[2]

- Risk of these chemicals to consumers is probably very low[2]

Hormones –

Xenobiotics (not

naturally

occurring, usually

synthetic)

Trenbolone.

Melangestrol.

Zeranol (non-

steroidal anabolic

agent). Stilbenes.

Beta-agonists

(clenbuterol,

salbutamol))

- Any amount found of these hormones is contaminant[2]

- Beta-agonists are used (illegally) to make the carcases/meat leaner. Can cause muscle

tremors, headaches, increased heart rates etc.[2]

- Risk of these chemicals to the consumer is based on the observation of the withdrawal

periods (where legally) and is considered as low. In the cases of illegal administration

though the risk is higher (e.g. beta-agonists)[2]

- A study on zeranol, trenbolone, oestradiol, progesterone and testosterone by Lemming

et al, 1987, has not shown any adverse effects on the human health (cited by Gracey,

1999)

Industrial

chemicals

PCP. PCDD/PCDF

(= dioxins). HCB.

PCBs.

- Entering the food chain through contamination of feed, water or the environment[3]

- PCP most toxic of all. Used as wood preservative. By-products of the production of

these chemicals include dioxins, themselves extremely toxic to humans[3]

- Dioxins are by-products of various incineration and high temperature processes.

Extremely toxic, carcinogenic, teratogenic and immunosuppressive. Clinical picture

includes CNS and PNS signs, liver toxicity etc.[3]

- HCB: Pesticide (fungicide). Use has stopped in most of the world because of

bioaccumulation and toxic and other effects (stillbirths, photosensitisation etc.).

Carcinogenicity probable but not proven[3]

- PCBs: wide use in industry. Possibly carcinogenic[3]

Project MC1003 2010


Essential

minerals/metals

- Entering the food chain mainly through excessive (accidental) use to, or ingestion by,

the animals when supplied as supplementary products. In high doses they can cause

toxicity to animals and humans. Examples include:

- Zinc[3]

Selenium - Teratogenic. Haemolytic anaemia. Acute form: fever, vomiting, nervousness etc.

Chronic form: depression, loss of hair/nails etc.)

Non essential

metals (Hg, Cd,

Pb, As)

- Entering the food chain through contamination of feed, water or the environment[3]

- Mercury (Hg): nervous signs[3]

- Cadmium (Cd): Chronic toxicosis: nephrotoxity, osteomalacia, osteoporosis etc. Very

long half-life in humans (therefore high accumulation in body)[3]

- Lead (Pb): Carcinogenic[13]. Absorbed much more in children. Effect on kidneys and

nervous system[13]. Affects embryo (brain) development[3]. Affects brain development

and cognitive ability of children[9][13] Anaemia. Cardiovascular disease. Neurological

defects in children[11]

- Arsenic (As): Was widely used in pesticides etc. Carcinogenic[3]

- Cadmium: Toxic to kidney. Bone demineralisation. Carcinogen[11][12]. Meat did not

figure high in source for cadmium for the human population[12]

Pesticides General - In Canada, 70% of the pesticides used were herbicides[4]

Insecticides

Organochlorines (

DDT),

organophosphates,

carbamates

- Prevalence of residues on carcases in Canada is very low. Risk to PH low[4]

- Human exposure to insecticides in decreasing. Risk to humans now takes the form of

“dramatic events” or “outbreaks” (i.e. accidental contamination of food with high

doses)[4]

- Insecticides are fat soluble and bio-accumulative, but the long term risks to humans are

not clear[4]

- DDT: affects reproduction and hormonal system, foetal development and the immune

system. Dramatic decline of human exposure to DDT over past decades.[13]



Project MC1003

Review of meat inspection controls WORKSHOP

“Development of a qualitative approach to assess the relative

effectiveness1 of the current meat inspection activities”

Project Report N.2 – Workshop report

Authors: Silvia Alonso, Lecturer in Veterinary Public Health


Neville Gregory, Professor in Animal Welfare Physiology


1 In the context of this project, “effectiveness” is understood as the capacity to detect a specific hazard to

public health, animal health and animal welfare (i.e. detection of the lesions associated with that hazard).

2



Workshop report – Research project MC1003

Royal Veterinary College, Camden Campus

12-13 October 2010

Participants

Silvia Alonso, Nikolaos Dadios, Katharina Stärk, Neville Gregory, Annette Nigsch

Royal Veterinary College (UK)

Luëppo Ellerbroek

Food Institute for Risk Analysis (Germany)

Lis Alban

Danish Agriculture & Food Council (DAFC) (Denmark)

Bojan Blagojevic

University of Serbia

Liz Redmund, Oufa Doxon

Food Standards Agency

(For agenda, see annex 1)

Background

In the context of project MC1003, a workshop was organized with the international partners

of the project, and invited stakeholders, to discuss the project progress and plan future

activities. The specific objectives of the workshop were:

1. To discuss approaches to the evaluation of meat inspection practices (based on

experiences from other countries, if available).

2. To exchange information on activities on this area (revision of meat inspection

controls, evaluation of alternative systems for meat inspection,...) that have been or

are being investigated in other countries (especially Europe).

3. To create the basis to develop a tool for effectiveness assessment of inspection

tasks.

3



The workshop was an opportunity to share experiences in relation to the revision of meat

inspection controls in different European countries. It was also a platform to revise the work

achieved so far in the project, and the future steps. This report outlines the main points of

discussion.

Summary of discussions

� Presentation of general activities in the context of review of meat inspection controls

in the countries represented in the workshop.

Participants presented recent advances, investigations and developments in terms of meat

inspection control in their respective countries.

DENMARK – the revision of the current meat inspection system has been driven mainly by

industry (DAFC is a corporation owned by the farmers that assists the Danish

slaughterhouses in their work – the slaughterhouses are also owned by the farmers). In light

of this and the specific type of pig production in the country (i.e. good traceability in general

and concentration of slaughtering on a limited small number of slaughterhouses) stimulates

the interest of the sector in reconsidering potential options for improved inspection and

facilitates discussion and action. The current disease status of the country is essential in

framing the context and makes a “risk-based programme for meat inspection possible. It was

highlighted that the revision of the meat inspection was also conditioned by the current

trade situation in the country (large export to USA). Main concerns in the revision of

inspections are: (i) consumer reactions – of particular relevance when considering potential

changes; (ii) notifiable diseases – this is particularly relevant in relation to trade within EU

and with third countries; (iii) animal health – changes in meat inspection should preferably

be coupled with a veterinary service that constantly increases focus on advisory service

rather than treatments (iv) animal welfare.

To date the revision of meat inspection is targeting finisher pig production, and specifically

“integrated production systems”. This implies a specific set of requirements to biosecurity

defined in Regulation 1244/2007 has to be met.

GERMANY – Germany has become more self-sufficient in pig meat production in recent

years. The production systems are more diverse than in Denmark, with different

slaughtering systems (small to large plants) across regions in the country. Moreover, the

meat production industry is less influenced by exports. Mainly the big slaughterhouses are

the ones advocating and driving changes to the meat inspection system, making use of the

flexibility allowed for in the current legislation. At the moment, visual meat inspection is

possible (if specific criteria are met by the plant) for slaughtered pigs and calves. The country

4



is also exploring novel diagnostic tools that could substitute some of the current inspection

practices.

UNITED KINGDOM – The current focus is the gathering of scientific evidence to support a

revised inspection control system, including risk based inspection. The first step in a

potentially revised system would be to move within the flexibility allowed for in the current

legislation. It was emphasized that, in this country, industry is not the driving force in the

revision of meat inspection, but the public sector.

In this context, the Food Standards Agency is commissioning a number of research projects

as part of specific requirements set by the Agency.

� Presentation on project aims and update on progress and results

The project aims and objectives were briefly presented, structured in three main parts: (i)

hazard-inspection matching, (ii) effectiveness assessment tool and (iii) risk assessment

framework.

i. Hazard-risk mapping

The results of the first report (Project report N.1 - public health hazards) were visited and

discussed. The methodology used and the results obtained to date were very welcome

by the participants. There were no major comments on the approach used.

The approach envisaged for exploring Animal Health (AH) and Animal Welfare (AW)

hazards was presented and discussed.

Animal health – Hazards (diseases) are to be identified among notifiable diseases; it was

agreed that only those hazards for which a routine collection and use of data currently

exist are the ones that may potentially be impacted by a revision of meat inspection.

Members of the research team have been invited to attend an FSA-DEFRA-AHO meeting

next November 12, where priorities for AH and AW will be discussed. It was noted that

the outcome of that meeting will not influence the direction of our work as our report

on AH hazards is due before the meeting. The identification of AH hazard will focus on

diseases (i.e. agent focus) rather than syndromes.

Animal welfare – Due to very limited available literature relating to hazards on this

topic, the assessment of hazards is to be done using expert opinion (online

questionnaire). The idea was well received by the participants. The newly published “EU

quality welfare reports” were suggested as another source of information for this

specific part of the project, but it was recognised that some of the assessment criteria

would be too lengthy and involved for the approach needed for the present application.

It was concluded that guidance is needed from DEFRA through the FSA on what the

5



goals are in using PMI as a way of monitoring animal welfare. More specifically, are the

goals (i) limited to stock raised for slaughter or do they encompass breeding stock (ii)

intended to encompass suffering associated with disease, and if not what should be

included (iii) intended to ascribe culpability to particular sectors (iv) to assist with

constructing a surveillance system that could be used as a modifier in the single farm

payment system or any other subsidy system for farmers.

ii. Effectiveness assessment tool

This aspect was the principal focus of the workshop. Discussion on criteria to be

included in the assessment of effectiveness of meat inspection tasks concluded the

following:

Two main criteria to be the basis of the effectiveness assessment were identified:

� Sensitivity - “proportion of actual positives that are identified as positives” (e.g.

the proportion of offal with a specific hazard that is identified as positive for

that hazard)

� Positive predictive value, PPV (influenced by prevalence and related specificity)

– “probability that a hazard identified as such is really that hazard” (e.g. the

proportion of offal that has a specific hazard among those that are “diagnosed”

with it).

Assumptions that will underlie the assessment of effectiveness:

� Knowledge/awareness of hazards (particularly relevant in the case of emerging

hazards): inspectors and official veterinarians need to be, at every moment,

appropriately aware and have adequate knowledge to detect with 100%

sensitivity and specificity a hazard.

� Layout of the plant (particular case of AW hazards): the effectiveness tool will

assume a specific scenario (that will reflect, where possible, the most common

plant layout in the UK) and any outcomes of the assessment tool will relate to

this specific scenario.

� Time for inspection: Meat inspectors have enough time to appropriately inspect

each viscera. This assumption is supported by the “business agreement” that

requires plants to adjust the number of personnel employed according to the

throughput. It is assumed that plants in the UK operate on this basis.

Further comments:

6



The report should make clear that the outputs are based in, and relevant to, the UK.

Effectiveness is understood in this project as: “the probability of a specific meat

inspection task of detecting a specific hazard” or, briefly, “detection capacity”.

The importance of defining who will be the end-users of the assessment tool was raised

as a question. Policy makers (FSA) will be the ultimate users of this tool. It is meant to

provide a solid/scientifically valid estimate of the relative effectiveness of specific meat

inspection tasks. Another aspect that may be relevant in the evaluation of effectiveness

would be “costs”. It was agreed that, at this point in time, we should not consider this

aspect, as the aim of the exercise is to produce evidence on relative “detection

capacity”.

Discussion arose regarding the availability of data to be used in the effectiveness

assessment (Sensitivity and PPV). The sources of info will be scientific literature or,

when not available, expert consultation.

It may be necessary to include also as an assessment criteria “the proportion of animals

that present with that lesion” or “likelihood of a hazard to present with a lesion”. No

agreement was obtained on this point, but it will be considered while developing the

tool.

Potential outputs from the tool:

• Quantitative measures (low, medium, high) of effectiveness of an inspection task

for a specific hazard.

• Identification of tasks that have low/high effectiveness for all considered hazards.

• Evaluation of lesions (related to AW, AH, PH respectively) and identification of the

most effective tasks for assessing those lesions.

It was clarified that the project will not evaluate systematically all identified hazards, but

will only undertake a pilot assessment for a selection of hazards to evaluate the

usefulness and rigour of the tool.

iii. Risk assessment framework

The concept of the risk pathway for the assessment framework was presented and

discussed. The following are the principal aspects raised during discussion:

� The risk pathway could contain the following three aspects: steps in production,

characteristics of the hazard and control options.

7



� The inspection tasks will be incorporated in the risk pathway, as part of the “controls”.

� Identification of hazards to be “risk assessed” could be done by focusing on hazards that

can be detected during offal inspection (as this is the focus of FSA requirement). The risk

assessment will though evaluate the risk from farm to chiller.

� The risk assessment will probably depend on the population we are looking at (i.e. young

vs old animals; integrated vs not-integrated production systems). The population the

assessment refers to should be explicitly presented in the assessment report.

Conclusions

The workshop was beneficial to the progress of the project. It provided an opportunity to

discuss plans and relevance of the work. While the activities in the context of this research

project focus on production of sound evidence for decision making, it was emphasized

during the workshop that any revision of meat inspection should be made after careful

evaluation of the country-specific conditions, and after appropriate cost-effectiveness

assessment of potential changes. This is likely to depend on the meat production system in

the country and the driving forces for change. The team in this project strongly supports this

view and remarked that the role of the specific work being done in the context of project

MC1003 is to provide “scientifically sound” strategies for the evaluation of effectiveness of

specific meat inspection tasks. These assessments cannot be used as the sole source of

information for decision making. An evaluation of impact (at many levels) should be made

before recommendations for a revised meat inspection system are made.

8



Annex 1. Workshop agenda (as circulated before the workshop)

Review of meat inspection controls WORKSHOP

RVC Camden Campus, Royal College Street, NW1 0TU, London

12-13 October 2010

“Development of a qualitative approach to assess the relative effectiveness2 of the current meat

inspection activities”

(project funded by the Food Standards Agency)

Participants: Katharina Stärk (RVC, Safoso), Lis Alban (DAFC, Denmark), Lüppo Ellerbroek

(Bundesintitut für Risikobewertung, Germany), Ouafa Doxon (Food Standards Agency, UK), Neville

Gregory (RVC), Nikolaos Dadios (RVC) and Silvia Alonso (RVC).

Aim and objectives of the workshop

To discuss approaches to the evaluation of the effectiveness of the current meat inspection tasks and

development of a framework for this type of assessment, specifically:

1. To discuss approaches to the evaluation of meat inspection practices (based on experiences from

other countries, if available).

2. To exchange information on activities on this area (revision of meat inspection controls, evaluation

of alternative systems for meat inspection,...) that have been or are being investigated in other

countries (especially Europe).

3. To create the basis to develop a tool for effectiveness assessment of inspection tasks.

Material to be prepared by participants

1. Information (scientific and grey literature) on activities/research undertaken in your (and other)

countries in terms of (i) evaluation of effectiveness of meat inspection practices, (ii) revision of meat

inspection and (iii) risk assessments in relation to meat production.

2. A proposal on a method for the evaluation of effectiveness of meat inspection practices (inc.

parameters that may be relevant in measuring effectiveness, technical aspects,...)

3. List of sources of information for point 1 and 2 above.

2 In the context of this project, “effectiveness” is understood as the capacity to detect a specific hazard to

public health, animal health and animal welfare (i.e. detection of the lesions associated with that hazard).

9



Workshop agenda (subject to changes)

Tuesday 12 October

14.00 – Introduction and presentations

14.30 – Presentation of the project funded by FSA (Silvia Alonso)

15.00 – Development of an effectiveness assessment tool (all participants)

a) Presentation of experiences in other countries

b) Discussion on parameters/criteria to be used in the assessment

c) Discussion on a suitable framework for the assessment tool

17.30 – Summary of discussions day I and conclusions

18.30 – Informal dinner (Liz Redmond (FSA), and participants)

Discussion on revision of meat inspection controls in Europe – where are we? How

achievable? What directions?

Wednesday 13 October

8.30 – Coffee (final aspects from Tuesday discussions)

9.00 – Presentation FSA project (part II) – Risk assessment (Silvia Alonso)

10.00 – Review of meat inspection controls (all participants)

A) Presentation by participants - activities being carried out in European countries

b) Risk assessments for public health, animal health and animal welfare

12.30 – Summary of discussions day II and conclusions

13.00 – Lunch

14.00 – Any other business



Project MC1003

Assessment of benefit to public and animal health of post-mortem inspection of green offal in red meat species at slaughter

and

Outcomes and values of current ante- and post-mortem meat inspection

tasks

Project Report N.3: A generic risk pathway of inspection tasks currently undertaken during slaughter and at primary production level.

Authors: Annette Nigsch, Resident of the European College of Veterinary Public Health

Silvia Alonso, Lecturer in Veterinary Public Health

Nikolaos Dadios, Research Assistant



MC1003 – Report N.3 2010

2 Assessment of benefit to public and animal health of post-mortem inspection of green offal in red meat species at slaughter – RISK PATHWAY

Assessment of benefit to public and animal health of post-mortem inspection of green offal in red meat species at slaughter


PROJECT REPORT N.3 (Objective 4) – A generic risk pathway of

inspection tasks currently undertaken during slaughter in accordance

with Annex I of Regulation (EC) 854/2004, covering as well primary

production and transport of animals to the slaughterhouse.

SCOPE OF STUDY

This report outlines the activities conducted and results obtained as part of the forth

objective of the project MC1003. Strategy and results of objective 2 “List of hazards,

its associated conditions and suitable inspection tasks” (delivered 31.10.10) and

objective 3 “Report of expert workshop” (delivered 28.10.10) have been taken in

account in this document.

The scope of the objective topic of this report was to create a generic risk pathway of

meat inspection by mapping inspection tasks at slaughterhouse level, during

transport and at primary production level. This generic model sets hazard level,

controls and actions (see chapter 6.5) from farm to slaughterhouse in interaction.

This shall allow a future evaluation of the impact of different control practices on the

“level” of risk associated to hazards in the meat production and will form the basis of

objective 5 “Evaluation of risk for public health associated with the current green

offal inspection activities”.

The project focus is on red meat production, and specifically cattle, pig and small

ruminants.

MC1003 – Report N.3 2010


BACKGROUND

Since 1964, food hygiene has been incorporated in the legislation of the European

Union (EU); consumer protection, animal health and official controls were included

in many legislative texts.

A key policy priority of the European Commission (EC) is assuring that the EU has

the highest standards of food safety. This priority is reflected in the White Paper on

Food Safety which was published in 2000 (EC, 2000). The guiding principle

throughout the White Paper is that food safety policy must be based on a

comprehensive, integrated approach. This means throughout the food chain “farm to

table” (EC, 2000).

1. Food chain approach – links in the food chain

The European food safety legislation covers all aspects of food products from “farm

to table”. It deals with the hygiene of food in a horizontal way, including feed

production, primary production, food processing, storage, transport and retail sale.

This integrated approach is necessary to ensure food safety from the place of primary

production up to and including placing on the market or export (Reg. (EC) 852/2004).

Every food business operator along the food chain should ensure that food safety is

not compromised as each element may have a potential impact on food safety

(Reg. (EC) 178/2002).

Directive (EC) 2160/2003 points out the need for controls covering the whole food

chain. Targets to reduce hazard level and consequentially public health risk may be

established in respect to other parts of the food chain, where necessary. This

approach to start with the control of food safety at primary production level is

already implemented for certain pathogens and production types of animals, e.g.

control of food-borne Salmonella in breeding hens, laying hens and broilers. A

reduction target for slaughter and breeding pigs is currently in discussion (EU, 2009).

2. Responsibilities

The scope of Regulation (EC) 852/2004 is to lay down

“general rules for food business operators on the hygiene of foodstuffs, taking

particular account of the following principles:

MC1003 – Report N.3 2010


(a) primary responsibility for food safety rests with the food business

operator;

(b) it is necessary to ensure food safety throughout the food chain, starting

with primary production.”

This legislative text lays down minimum hygiene requirements and requirements for

food business operators to establish and operate food safety programmes and

procedures based on the HACCP principles. These measures focus on satisfaction the

relevant hygiene requirements at all stages of production, processing and

distribution of food under their control, as laid down in legislation

(Reg. (EC) 852/2004).

In parallel, the role of official controls is to check food business operators' compliance

with European legislation and its correct implementation by the food business

operator. Furthermore, the competent authority is responsible for public

communication on food safety and risk.

3. Animal Health and Welfare

The health and welfare of food producing animals is essential for public health and

consumer protection (EC, 2000). Diseases like tuberculosis and salmonellosis have

zoonotic character and can be transmitted from animals to humans through ingestion

of contaminated food. Zoonoses can show mild symptoms or even lead to life-

threatening conditions in humans (EFSA, 2010).

Animal welfare is specifically addressed in Regulation (EC) 853/2004 and Regulation

(EC) 854/2004 - the latter laying down the role of the official veterinarian in the

control of animal welfare rules concerning protection of animals at the time of

slaughter and during transport.

Regulation (EC) 853/2004 highlights existing interactions between food business

operators, including the animal feed sector, and connections between animal health,

animal welfare and public health considerations at all stages of production,

processing and distribution. This link is reflected in the common form of the EU

framework on food hygiene, animal welfare and animal health legislation.

MC1003 – Report N.3 2010


4. Introduction to the generic model

To better understand the effectiveness of control tasks at slaughterhouse level - e.g.

meat inspection tasks - in relation to the risk for public health, animal health and

animal welfare associated with the meat production system it is important to explore

sequential steps in animal production and to investigate factors that contribute

potentially to the risk either by increasing or decreasing the quantity of hazards in

fresh meat.

In the generic model presented in this report the food chain approach is taken into

account as control tasks are described and mapped over various steps from primary

production level to transport and slaughterhouse level. The model follows the risk

assessment framework of the Codex Alimentarius.

The European legal framework on food safety and hygiene was used to identify

responsibilities of food business operators, slaughterhouse operators and control

activities of the competent authority. This information serves as input to the generic

model.

MC1003 – Report N.3 2010


MATERIALS AND METHOD

Firstly, basics of the risk assessment framework of the Codex Alimentarius will be

described to put the outcomes of this report into context with the next step - objective

5 – of the whole project. Secondly, the development of the risk pathway and also

characterisation and identification of controls will be explained. Concluding, the

European legal framework is outlined which gives basis to the risk pathway and

control tasks to be carried out in the food chain.

5. Risk assessment – Codex Alimentarius framework

The White Paper on Food Safety recognizes risk analysis as the foundation on which

food safety policy is based. Food policy shall be directed on the application of the

three components of risk analysis: risk assessment (scientific advice and information

analysis), risk management (regulation and control) and risk communication

(EC, 2000)

The generic model for abattoir meat inspection is created following the risk

assessment framework of the Codex Alimentarius Commission. In this framework

the risk assessment follows a structured approach (FAO/WHO, 2010):

• Hazard identification: The identification of biological, chemical, and

physical agents capable of causing adverse health effects and which may

be present in a particular food or group of foods.

• Hazard characterization: The qualitative and/or quantitative evaluation

of the nature of the adverse health effects associated with biological,

chemical and physical agents which may be present in food. For

biological or physical agents, a dose-response assessment should be

performed if the data are obtainable.

• Exposure assessment: The qualitative and/or quantitative evaluation of

the likely intake of biological, chemical, and physical agents via food as

well as exposures from other sources if relevant.

• Risk characterization: The qualitative and/or quantitative estimation,

including attendant uncertainties, of the probability of occurrence and

severity of known or potential adverse health effects in a given

population based on hazard identification, hazard characterization and

exposure assessment.

MC1003 – Report N.3 2010


A comprehensive list of hazards to public health (PH), animal health (AH) and

animal welfare (AW) related to meat production was identified in objective 1 of the

joint project MC1003 and MC1R0001 (see report N.1) with hazards being carefully

selected in respect to their importance and impact on PH, AH and AW. That work

corresponds to the step of hazard identification.

Hazard characterization, risk characterization, exposure assessment and the

qualitative risk assessment per se will be the subject of objective 5 of this project,

which focuses on the evaluation of risk for public health, animal health and animal

welfare associated with the current green offal inspection activities. Note that, in the

context of this project, “risk” is understood as the probability of contaminated

carcases leaving the slaughterhouse into human consumption and the potential

consequences of such contamination.

This report presents the development of the risk pathway.

6. Description of risk pathway

With the description of the risk pathway the steps necessary for the unwanted output

of interest to occur are set out. At the basis of these steps, data required for the

qualitative risk assessment will be identified and the use of such data will be

determined.

Every single step of the risk pathway is linked to a probability (P) that the hazard of

interest is present and a level or concentration (N) of that hazard in the animal or

carcase. On the basis of these two factors the exposure can be assessed.

6.1. Probability

Probability (P): P measures the likelihood of presence of a hazard; in other terms:

prevalence of infection, colonisation or contamination with a hazard X or presence of

a condition X (in respect to animal welfare) in/on an animal or carcase.

6.2. Hazard level

Hazard level (N): N refers to the quantity of a certain pathogen an animal or animal

carcase incorporates or is superficially contaminated with. Depending on the

characteristics and physiology of the pathogen of interest this quantity may vary

during the animal’s production cycle. Some pathogens are transmitted vertically,

MC1003 – Report N.3 2010


resulting in prenatal infection (e.g. BVD in calves); other pathogens will be picked up

predominantly by a certain group of animals (e.g. Trichinella in free ranging pigs,

parasites in young animals) or at a certain stage of the food chain (e.g. cross-

contamination with Salmonella spp. on the slaughter line).

Following the steps of the risk pathway the level of hazard X in/on an animal or

carcase can either increase or decrease. The unit of hazard (log concentration in

faeces, number of parasites, etc.) is not specified in this generic model.

Within animal welfare the terms “level of infection” or “level of contamination with a

hazard” may be less suitable. In this case hazard is understood as presence of a

condition X, e.g. a broken leg or tail bite.

6.3. Interaction of control and action

Two particular important elements in the risk pathway are formed by controls and

consecutive corrective action. Control and action go hand in hand: by means of a

control a deviation from the condition aimed for to the actual condition can be

recorded. The result of the control itself does not change a condition as far as a

corrective action does not follow.

For this “duet” of control and action (P) and (N) will be considered with following

approach:

(P) for control and consecutive corrective action is a combination of

• Probability (P) that hazard X is detected with the respective control

• Probability (P) that corrective measure is taken

(N) refers to the level of hazard X in/on an animal or carcase after application of the

corrective measure. This factor includes both positive (level of hazard X decreases as

a consequence of the corrective action taken) and negative effects of the controls

(increase of hazard level due to probable cross-contamination).

In relation to meat inspection tasks removal of hazard, condemnation of organ or

condemnation of the whole carcase are options for corrective actions.

6.4. Control

Regulation (EC) 882/2004 describes control activities as tasks related to official

controls which shall, in general, be carried out using appropriate methods and

techniques such as monitoring, surveillance, verification, audit, inspection, sampling

MC1003 – Report N.3 2010


and analysis. Inspection is referred to as one of several methods and techniques of

control.

As the model aims at embracing various steps of the food chain, the term “control” is

used to cover the full range of checks carried out. In this sense control can either

stand for official controls by the competent authority or (self-) control by the food

business operators themselves or stakeholders (as private veterinary service or

voluntary partnerships, see results section) contracted to conduct certain control

tasks.

6.5. Action

In general, actions taken as response to controls may range from culling measures,

medical treatment, preventive measures, changes in housing conditions, etc. to doing

nothing. In the same way, effectiveness of actions undertaken will range from

positive effects to no effects – or even to negative effects (i.e. increase of hazard level).

In the generic model the effect of an action will be displayed in form of a resulting

change of the level of hazard X in/on an animal or carcase.

Furthermore the frequency of action-taking may vary from daily (e.g. alertness of

food business operator leading to immediate action) to once in the lifetime of the

single food producing animal.

7. Characterisation and identification of controls

To account for the particular role of controls in this project, respectively meat

inspection tasks, control types along the food chain were characterised and control

tasks were identified. This information will help to give frame to the data needed as

model input.

To cover both pre-and post harvest areas of the food chain the collection of

information on controls ranged from primary production to transport and

slaughterhouse.

7.1. Characterisation of control types

Roles and responsibilities in relation to controls in meat production were identified.

Two important actors are food business operator and competent authority. The food

business operator has responsibility to “ensure that the requirements of food law are

met within the food business under their control” (Reg. (EC) 178/2002). The

competent authority’s duty is to “enforce feed and food law, animal heath and

MC1003 – Report N.3 2010


animal welfare rules and monitor and verify that the relevant requirements thereof

are fulfilled by business operators at all stages of production, processing and

distribution. Official controls should be organised for that purpose” (Reg. (EC)

882/2004).

7.2. Identification of control tasks carried out

To identify control tasks at primary production level, during transport and at

slaughterhouse level the legislative texts listed in section 4 “Legal base” were

screened. Both controls with public health relevance and text passages laying down

requirements in respect to animal health and animal welfare were collected and

allocated.

The listed tasks shall give an overview of control tasks laid out in respective

legislation. Control tasks were identified by collecting information on tasks that were

particularly assigned to these persons; e.g. conditions to ensure, guarantees to give,

obligations to meet, etc.

According to Regulation (EC) 882/2004 tasks related to official control activities

“shall, in general, be carried out using appropriate control methods and techniques

such as monitoring, surveillance, verification, audit, inspection, sampling and

analysis.”

Listing of inspection tasks will be done in detail for inspection tasks at

slaughterhouse level as set out in Annex 1 of Regulation (EC) 854/2004.

8. Legal base

The European legislation framework on food hygiene, animal welfare and animal

health legislation is based on a horizontal approach for all food safety and hygiene

rules. This was set out as prerequisite to give the legal acts ability to take rapid,

effective, safeguard measures in response to health emergencies throughout the food

chain (EC, 2000).

The generic model is based on the assumption that legal requirements on controls to

be carried out are met and that requirements on structural conditions of

establishments and good practices are fully implemented.

MC1003 – Report N.3 2010


Common basis for the food safety and hygiene law is Regulation (EC) 178/2002

(General principles and requirements of food law). This text complemented by

legislation addressing specifically the food business operator and official controls.

Food business operator:

• Regulation (EC) No 852/2004 (General rules on hygiene of foodstuffs);

• Regulation (EC) No 853/2004 (Specific hygiene rules for food of animal origin).

Official controls:

• Regulation (EC) No 882/2004 (General rules for official feed and food

controls);

• Regulation (EC) No 854/2004 (Specific rules for official controls on products of

animal origin intended for human consumption).

Legislative texts which determine compliance rules for topics closely related to the

hygiene legislation:

• Regulation (EC) 999/2001 (TSE);

• Directive 2002/99/EC (Animal health);

• Regulation (EC) No 2160/2003 (Zoonoses control food-borne zoonotic agents);

• Regulation (EC) No 1069/2009 (Animal by-products).

Following legislation addressed implementation criteria:

• Regulation (EC) No 2073/2005 (Microbiological criteria);

• Regulation (EC) No 2074/2005 (Implementing measures);

• Regulation (EC) No 2075/2005 (Trichinella testing).

Rules for animal welfare during transport and slaughter are laid down in:

• Directive 64/432/EEC (Transport in general and in relation to animal welfare);

• Regulation (EC) No 1/2005 (Animal welfare during transport);

• Directive (EC) 1099/2009 (Animal welfare during slaughter and killing).

MC1003 – Report N.3 2010


RESULTS

In the first part of the results section the generic risk pathway will be described. The

second part focuses on the characterisation and identification of controls. Only the

structure of the information gathered is presented in this section. For detailed lists

see Annex 1 (Primary production level), Annex 2 (Transport) and Annex 3

(Slaughterhouse).

9. Description of the steps in the risk pathway at primary production, during

transport and at the slaughterhouse

The risk pathway of the food chain is split up into main and sub-stages. For each

stage, the probability and level of hazard presence is then described.

The risk pathway concentrates on production stages at primary production level,

transport of animals to the slaughterhouse and slaughter. In relation to slaughter the

inspection tasks of the competent authority are mapped.

Note: Data availability on single steps of the risk pathway may vary between

hazards, species and different aspects of risk (PH, AH, AW). As a consequence,

single steps of the risk pathway will have to be combined in a reasonable manner

when the risk assessment is undertaken for a specific hazard.

In general, many other inputs are required to model food-borne disease risk from

primary production to slaughterhouse level. These factors of potential concern

include inter alia intrinsic and extrinsic factors in relation to the health and welfare

status of an animal as well as controls and corrective human interactions during the

whole production cycle.

Depending on data availability these potential factors will be taken in account for the

actual application of the model.

Structure of the risk pathway

• Black bullet points mark sub-stages on the risk pathway;

• White bullet points specify processes which occur in this sub-stage (left column).

For every stage the output is described with the two factors probability (P) and level

(N) of hazard X, see right column.

13 Assessment of benefit to public and animal health of postgreen offal in red meat species at

Figure 1: Generic risk pathway for hazard X from farm to

MC1003 – Report N.3

Assessment of benefit to public and animal health of post-mortem inspection of green offal in red meat species at slaughter – RISK PATHWAY

Generic risk pathway for hazard X from farm to slaughterhouse.

Report N.3 2010

mortem inspection of

MC1003 – Report N.3 2010


9.1. Primary production unit

The risk pathway (tab. 1) starts with the ultimate primary production unit / farm

from where animals directly are sent to the slaughterhouse and not in any way

distributed to other farms (by direct trade, through markets, etc.).

Uncertainty linked to an animal’s health status that was held at more than one farm

during its production cycle will be taken in account in the generic model with the

first sub-stage on the risk pathway: by use of a probability the provenance of the

animal can be specified. Animals can either be classified as born on the farm or as

purchased (irrespective of the number of farms where they used to life before).

Table 1: Steps of the risk pathway at primary production level. The output section details probabilities of presence and level of a hazard X.

Primary production unit

Main and sub-stages on pathway Output

• Entry of the primary production unit / farm through birth of animal or purchase of animal

• PFarm1a: probability that animal is born on farm

• PFarm1b: probability that animal is purchased (not born on farm)

• Health status of the animal at entry into the farm • PFarm2: probability that animal is infected / hazard X is present

• NFarm2: level of hazard X in/on an animal at entry into the farm

• Production cycle o Growing and fattening

Factors of potential concern which have to be considered for

collection of data: o Intrinsic factors

� Purpose of animal, breed, immunity, etc. o Extrinsic factors

� Contact with animals of unknown health status � Feed, water source and access, environment,

pest, wildlife, etc. o Control

� (Self-) Control by FBO, official controls o Action

� Actions taken upon detection of hazard � Preventive measures (quarantine, vaccination,

etc.) Note: factors of potential concern, including controls and corrective actions, influence the prevalence / probability of presence of a specific hazard and the concentration / level on a daily base.

Generic approach to consider impact of factors of potential concern:

• PFarm3 – (n): probability that animals is infected / hazard X is present as a consequence of the effect of a certain factor

• NFarm3 – (n): level of hazard X in/on an animal as a consequence of the effect of a certain factor

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• End of production cycle • Prevalence of hazard at end of production cycle o Herd prevalence o Within herd prevalence o Number of herds o Number of animals in a herd

• Concentration / level of hazard X at end of production cycle

9.2. Transport

The stages of transport comprise loading, unloading, transfer and rest, until the

unloading of the animals at the place of destination is completed as outlined in

legislation (Reg. (EC) 1/2005); furthermore, controls and cross-contamination during

transport are included (see tab. 2).

Table 2: Steps of the risk pathway during transport. The output section details probabilities of presence and level of a hazard X.

Transport

Main and sub-stages on pathway Output

• Loading • PTransport1: Probability that hazard X is present after loading

• NTransport1: level of hazard X in/on an animal after loading

• Stop at assembly centre or control post

(n): Number of stops

• PTransport2a – (n): probability that hazard X is present after stop

• NTransport2a – (n): level of hazard X in/on an animal after stop

• Cross-contamination during transport o Shedding of hazard o Transmission of hazard o Cleaning and disinfection of transport vessel

• PTransport3: of cross-contamination during transport

• NTransport3: level of hazard X in/on an animal after cross-contamination

• Controls and corrective actions Controls include both (self-) controls by the transporter and official controls (n): Number of controls carried out

• PTransport4a – (n): probability that hazard X is detected with control

• NTransport4a – (n): level of hazard X in/on an animal after application of corrective measure

• Unloading • PTransport5: probability that hazard X occurs during unloading / Animal Welfare (AW)

• NTransport5: level of hazard X in/on an animal after unloading (AW)

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9.3. Slaughterhouse

Tab. 3 outlines the risk pathway at slaughterhouse level, starting from checking of

Food Chain Information (FCI) till application of the health mark and release of the

carcase.

It is acknowledged that single steps on the processing line are executed in parallel

with meat inspection (and not in succession), as pointed out in fig. 1. It is also

acknowledged that logistical layout of processing lines differs between

slaughterhouses, resulting in variation of the course of processing steps and meat

inspection tasks (MIT) at a certain time. As a compromise, processing steps and MIT

are mapped down one after the other in the tabular form.

For an evaluation of the effectiveness of a specific MIT the risk pathway will be

subject to adaption according to the explicit risk question.

Cross-contamination in the slaughter hall (e.g. due to splashing, physical contact

between two carcases, insufficient cleaning and disinfection of slaughter hall after

finishing slaughter process) and corrective measures (e.g. trimming and washing) are

not included as a stand-alone step in the risk pathway, but are included in (P) and

(N) of every single step.

Table 3: Steps of the risk pathway at slaughterhouse level. The output section details probabilities of presence and level of a hazard X.

Slaughterhouse: Main and sub-stages on pathway

Arrival Area & Lairage / Holding Pen Output

• Check FCI and (first) selection of animal for routine slaughter* o Check and analyse relevant information o Check any accompanying official certificates and

declarations made by veterinarians carrying out controls at the level of primary production

o Identification of animals which need to be put aside / require testing

• PLairage1a: probability that animal is subject to routine slaughter (and not put aside)

• PLairage1b: probability that hazard X is present in / on animal after selection for routine slaughter

• NLairage1: level of hazard X in / on animal if subject to routine slaughter (and not put aside)

• Ante-mortem inspection and (second) selection of animal for routine slaughter (responsibility of Official Veterinarian)* o Check if animal welfare has been compromised o Presence of any condition which might adversely affect

human or animal health o Check cleanliness of animal o Clinical inspection of animals put aside* o Verification of segregation of animals to be tested

• PLairage2: probability that hazard will be detected during ante-mortem inspection

• NLairage2: level of hazard X in/on an animal after ante-mortem inspection

• Cross contamination o Waiting in lairage area

• PLairage3: probability that cross-contamination occurs

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o Shedding of hazard o Transmission of hazard o Cleaning and disinfection of lairage area

• NLairage3: level of hazard X in/on an animal after cross-contamination

Slaughter hall Output

• Arrival in slaughter hall • PSlaughter1: Probability that hazard is present upon arrival in slaughter hall

• N Slaughter1: level of hazard X in/on an animal upon arrival in slaughter hall

• Stunning • PSlaughter2: probability that hazard X is present in / on carcase after stunning

• NSlaughter2: level of hazard X in/on carcase after stunning

• Hoisting and bleeding / collection of blood • PSlaughter3: probability that hazard X is present in / on carcase after bleeding

• NSlaughter3: level of hazard X in/on carcase after bleeding

• Removal hides / fleece / scalding • PSlaughter4: probability that hazard X is present in / on carcase after removal of hides

• NSlaughter4: level of hazard X in/on carcase after removal of hides

• Evisceration, removal edible and inedible offal

• PSlaughter5: probability that hazard X is present after evisceration

• NSlaughter5: level of hazard X in/on carcase after evisceration

• Splitting of carcase, if applicable • PSlaughter6: probability that hazard X is present after splitting

• NSlaughter6: level of hazard X in/on carcase after splitting

• Removal of Specified Risk Material (SRM), if applicable • PSlaughter7: probability that hazard X is present after removal of SRM

• NSlaughter7: level of hazard X in/on carcase after removal of SRM

Post-mortem inspection Output

• Obligatory* meat inspection tasks (MIT) according to Reg. (EC) 854/2004: visual, palpation, incision of: o Inspection of whole carcase, external surface o Head o Lungs o Oesophagus o Heart o Diaphragm o Liver o GI tract o Spleen o Kidneys o Genitals and assoc. Organs (adult animals only) o Pleura

• PMIT1 – (n): probability that hazard X is present after every single meat inspection task (MIT)

• NMIT1 – (n): level of hazard X in/on carcase after every single MIT

• PMIT(n): probability that hazard X is present after post-mortem

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o Peritoneum o Umbilical area (young animals only) o Joints (young animals only)

(n): Number of MIT to be applied

For a detailed list of all MIT specified for species (small

ruminants, cattle and swine) and for age groups (young animals

and old animals) see Annex 4.

inspection

• NMIT(n): level of hazard X in/on carcase after post-mortem inspection

Note: visual inspection, palpation and incision of a single organ are considered to be three individual MIT

Laboratory testing Output

• Verification of compliance with the rules and criteria laid down in legislation in respect to microbiological criteria o Aerobic colony count; o Enterobacteriaceae; o Salmonella; o Examination for Trichinella infestation in carcases of

domestic swine; o TSE testing – depending on surveillance sub-population,

age-category and sampling rules set out in national program.

o Detection of unauthorised substances or products, control of regulated substances;

o Detection of OIE list A and, where appropriate, OIE list B diseases,

• Any other necessary laboratory testing.

• PLab1: cross contamination of carcase with hazard X due to unhygienic sampling procedure

• N Lab1: level of hazard X in/on carcase after sampling

Chiller Output

• Chilling of carcases o Cross contamination during chilling o Detention of carcases / hides till test results are received

• PChill1: cross contamination with hazard X in the chiller / contact between edible and non-edible

carcases

• NChill1: level of hazard X in/on carcase after cross contamination in the chiller

Release (for further processing) Output

• Release and despatch of carcases o Application of health mark to carcase and offal (or

disposal)

• PRelease1: probability that hazard X is present on carcase when released from slaughterhouse

• NRelease1: level of hazard X in/on carcase when released from slaughterhouse

* The risk pathway focuses on animals (and carcases thereof) which are subject to routine slaughter

and follow the main risk pathway (see risk path diagram, fig. 1). Only application of obligatory meat

inspection tasks is included in this pathway. Animals put aside (see fig, 1 – in lairage) or animals that

have to undergo emergency slaughter are not followed up as we assume that a range of additional

control tasks are applied to these animals. This handling and attention is deemed not to be

representative for the majority of animals sent to slaughter.

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10. Characterisation and identification of control tasks

The overview presented in this section is limited to the structure of the information

gathered. For a range of detailed tables see Annex 1 (Primary production level),

Annex 2 (Transport) and Annex 3 (Slaughterhouse).

10.1. Control tasks at primary production level

Without prejudice to the food business operator and the competent authority as main

actors two additional control types are listed (private veterinary service and

voluntary partnership). The reason for this is to point out presence of additional

stakeholders at the farm establishments and complexity of interaction of hazard

level, control activities and actions taken.

10.1.1. Characterisation of controls carried out at primary production level

See Annex 1, tab. 4 – 7 for a characterisation (type, tasks and frequency) of controls

carried out by following stakeholders:

• Food business operator

• Private veterinary service

• Voluntary partnership

• Competent Authority

10.1.2. Identification of control tasks carried out at primary production level

The food business operator shall, as appropriate, adopt the following specific

measures (see Annex 1, tab. 8):

• General hygienic measures

• Sampling and analysis

• Food hygiene measures / quality management

• Animal welfare

• Record keeping

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Private veterinary service:

The control tasks undertaken are dependent on the (oral) contract between food

business operator and veterinarian (see Annex 1, tab. 9).

Voluntary partnership:

Compliance of animal production and conditions, depending on the common

production strategy (see Annex 1, tab. 10).

Competent authority:

See Annex 1, tab. 11 for general obligations and control activities of the competent

authority.

10.2. Control tasks during transport from live animals to the slaughterhouse

Transport operations take place between primary production unit and

slaughterhouse. The main aim of controls in relation to transport is to check

compliance with animal welfare, hygiene and general transport requirements.

10.2.1. Characterisation of control types

Annex 2, tab 12 – 13 list characteristics (type, performer, tasks, frequency and

location) of controls during transport.

• Transporter or attendant


10.2.2. Identification of control tasks carried out before or during transport

A list of identified control tasks in relation to transport can be found in Annex 2,

tab. 14 – 15.

• Transporter or attendant


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10.3. Control tasks at the slaughterhouse

Regulation (EC) 852/2004 lays down criteria for food business operators to meet

obligations in relation to hygiene standards. Regulation (EC) 853/2004 lists

requirements of animals accepted onto the slaughter premise. Inspection tasks as set

out in Annex I of Regulation (EC) 854/2004 on the organization of official controls on

products of animal origin intended for human consumption are mapped in detail in

Annex 4.

10.3.1. Characterisation of control types

Characteristics (type, performer, tasks and frequency) of controls carried out at the

slaughterhouse are listed in Annex 3, tab. 16 – 17.

• Food business operator / owner and staff of the slaughterhouse


10.3.2. Identification of control tasks carried out at the slaughterhouse

An overview on control tasks specified in European legislation food safety and

hygiene is presented in Annex 3, tab. 18 – 19.

Food business operator:

• Objectives of HACCP-based procedures

• Animal welfare

• Hygiene of foodstuffs

• Other controls to be carried out according to multiple legislative texts

Competent authority:

According to Annex I of Regulation (EC) 854/2004 inspection at the

slaughterhouse include following tasks:

A. Food chain information

B. Ante-mortem inspection

C. Animal Welfare

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D. Post-mortem inspection

E. Specified risk material and other by-products

F. Laboratory testing

The official veterinarian will take account of results of audits carried out to

verify food business operator’s compliance with legal requirements.

Additional tasks include supervision of health marking, communication of

inspection results and decision making concerning live animals, animal

welfare and meat.

A detailed presentation of inspection tasks at the slaughterhouse can be found

in Annex 4, tab. 20.

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DISCUSSION

The White Paper on Food Safety (EC, 2000) advertised the ability of the new

European Legislation framework on food safety and hygiene to take rapid, effective,

safeguard measures in response to health emergencies throughout the food chain.

The imperative prerequisite is formed by availability of reliable data (WHO, 2001),

either in form of the relevant food chain information or results gained through

research.

Known limitations of this horizontal approach to the food chain are precisely data

gaps as records of integrated food-borne disease monitoring and surveillance

programs, including human food-borne illnesses, food-borne pathogens in food

animals and foods of animal origin demonstrate a substantial variation in quality and

validity (EFSA, 2010; WHO, 2001).

Identification of effective pre-harvest interventions for food-borne pathogens and

measurement and documentation of the contribution of pre-harvest interventions to

the reduction of food-borne illness was out of the scope of this study. Nevertheless

the generic model described here strongly relates to the link of controls and measures

taken during food production.

Application of the generic model to a real scenario will have to handle data gaps.

One strategy to tackle this challenge is to focus less on details of the risk pathway but

to evaluate the impact of measures in relation to their interactive role in the food

chain framework. In addition, alternative tools of data retrieval can be applied (e.g.

questionnaire survey or expert consultation).

The model will be adapted to fit the needs of the specific types of hazards under

consideration (i.e. AH, AW, PH).

The structured approach of the model will allow identification of the crucial step on

the integrated risk pathway where data gaps exist.

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REFERENCES

European Commission, 2000: White Paper on Food Safety. Commission of the European

Communities, Brussels, 12 January 2000, COM (1999) 719 final.

European Commission, 2009: Communication from the Commission to the European Parliament and

to the Council with regard to the state of play on the control of food-borne Salmonella in the

EU. Commission of the European Communities, Brussels, 29.5.2009, COM (2009) 250 final.

European Food Safety Authority, 2010: The Community Summary Report on Trends and Sources of

Zoonoses, Zoonotic Agents and foodborne outbreaks in the European Union in 2008. The

EFSA Journal (2010), 1496, Parma.

Food and Agriculture Organization / World Health Organization, 2010: Codex Alimentarius

Commission, Procedural Manual, 19th edition, Joint FAO/WHO Food Standards Programme,

FAO, Rome.

World Health Organization, 2001: Pre-harvest food safety. Report of a WHO consultation with the

participation of the Food and Agriculture Organization of the United Nations and the Office

International des Epizooties. WHO/CDS/CSR/EPH/2002.9. Berlin, Germany 26-28 March 2001.

European Legislation

Council Directive of 26 June 1964 on animal health problems affecting intra-Community trade in

bovine animals and swine (64/432/EEC).

Regulation (EC) No 999/2001 of the European Parliament and of the Council of 22 May 2001 laying

down rules for the prevention, control and eradication of certain transmissible spongiform

encephalopathies.

Council Directive 2002/99/EC of 16 December 2002 laying down the animal health rules governing the

production, processing, distribution and introduction of products of animal origin for human

consumption.

Regulation (EC) No 178/2002 of the European Parliament and of the Council of 28 January 2002 laying

down the general principles and requirements of food law, establishing the European Food

Safety Authority and laying down procedures in matters of food safety.

Regulation (EC) No 2160/2003 of the European Parliament and of the Council of 17 November 2003 on

the control of salmonella and other specified food-borne zoonotic agents.

Regulation (EC) No 852/2004 of the European Parliament and of the Council of 29 April 2004 on the

hygiene of foodstuffs.

Regulation (EC) No 853/2004 of the European Parliament and of the Council of 29 April 2004 laying

down specific hygiene rules for food of animal origin.

Regulation (EC) No 854/2004 of the European Parliament and of the Council of 29 April 2004 laying

down specific rules for the organisation of official controls on products of animal origin

intended for human consumption.

Regulation (EC) 882/2004 of the European Parliament and of the Council of 29 April 2004 on official

controls performed to ensure the verification of compliance with feed and food law, animal

health and animal welfare rules.

Council Regulation (EC) No 1/2005 of 22 December 2004 on the protection of animals during transport

and related operations and amending Directives 64/432/EEC and 93/119/EC and Regulation

(EC) No 1255/97.

Commission Regulation (EC) No 2073/2005 of 15 November 2005 on microbiological criteria for

foodstuffs.

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Commission Regulation (EC) No 2074/2005 of 5 December 2005 laying down implementing measures

for certain products under Regulation (EC) No 853/2004 of the European Parliament and of

the Council and for the organisation of official controls under Regulation (EC) No 854/2004 of

the European Parliament and of the Council and Regulation (EC) No 882/2004 of the

European Parliament and of the Council, derogating from Regulation (EC) No 852/2004 of the

European Parliament and of the Council and amending Regulations (EC) No 853/2004 and

(EC) No 854/2004.

Commission Regulation (EC) No 2075/2005 of 5 December 2005 laying down specific rules on official

controls for Trichinella in meat.

Commission Regulation (EC) No 1244/2007 of 24 October 2007 amending Regulation (EC) No

2074/2005 as regards implementing measures for certain products of animal origin intended

for human consumption and laying down specific rules on official controls for the inspection

of meat.

Regulation (EC) No 1069/2009 of the European Parliament and of the Council of 21 October 2009

laying down health rules as regards animal by-products and derived products not intended

for human consumption and repealing Regulation (EC) No 1774/2002 (Animal by-products

Regulation).

Council Regulation (EC) No 1099/2009 of 24 September 2009 on the protection of animals at the time of

killing.

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ANNEX

Annex 1. Controls – Primary production level

A.) Characterisation of control types

Table 4: Characterisation of control types at primary production level to be carried out by the food business operator.

Definition Food business operators are natural or legal persons responsible for ensuring

that the requirements of food law are met within the food business under their

control (Anonymous, 2002 - 178/2002)

Type Internal control, surveillance

Tasks The food business operator has the primary legal responsibility for ensuring food

safety at all stages of production, processing and distribution within the

businesses under her / his control (Anonymous, 2004 – 882/2004)

Frequency Observations are carried out on a daily base and are in a legal context summed

up under the term surveillance

Table 5: Characterisation of control types at primary production level to be carried out by the private veterinary service.

Type Internal control, expert advisory service

Tasks Depending on the (oral) contract between food business operator and

veterinarian; advice in public health, animal health and animal welfare issues, but

primary legal responsibility remains with the food business operator

Frequency May range between daily and rarely visits

Table 6: Characterisation of control types at primary production level to be carried out by voluntary partnerships (e.g. production co-operative).

Examples (Integrated) production co-operatives, breeding organizations, etc.

Type External control, quality control

Tasks Depending on the internal regulations of the partnership / co-operative and on the

contract between food business operator; Inspection tasks are carried out to

guarantee compliance of animal production and conditions with the common

production strategy

Frequency According to co-operative control protocol

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Table 7: Characterisation of control types at primary production level to be carried out by the competent authority.

Type Official control

Tasks Inspection tasks usually follow a detailed protocol; Official controls shall be carried

out at any of the stages of production, processing and distribution of feed or food

and of animals and animal products (Reg. (EC) 882/2004)

Frequency According to control protocol. They shall be carried out without prior warning and

may also be carried out on an ad hoc basis. Member States shall ensure that

official controls are carried out regularly, on a risk basis and with appropriate

frequency, so as to achieve the objectives of legislation (Reg. (EC) 882/2004)

B.) Identification of control tasks carried out at primary production level

Table 8: Identification of control tasks at primary production level to be carried out by the food business operator.

Hygienic measures

• Cleaning (and disinfection) of any facilities used to store and handle feed;

• Good condition of premise;

• Cleanliness of animals going to slaughter;

• Training and health of staff handling foodstuffs;

• Pest control.

Sampling and analysis • Notice of results of any relevant analyses carried out on samples taken from animals or other samples that have importance to human health.

Food hygiene measures /

quality management

• Compliance with microbiological criteria for foodstuffs;

• Procedures necessary to meet targets set to achieve the objectives laid down in legislation;

• Pre-harvest quality management;

• Good farming practices;

• Correct use of feed additives and veterinary medicinal products;

• Storage and handling of waste;

• Protection of primary products against contamination (as far as possible);

• Compliance with temperature control requirements for foodstuffs.

Animal welfare • General requirement.

Record keeping • Actuality of information on establishments provided to the competent authority;

• Correctness of food chain information;

• Health and identification marking of animal.

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Table 9: Identification of control tasks at primary production level to be carried out by the private veterinary service.

Dependent on the (oral)

contract between food

business operator and

veterinarian

• Health status of animals;

• Animal welfare;

• Use of veterinary medicinal products;

• Good hygiene practice, good farming practice;

• Performance of animal production in relation to food safety.

Table 10: Identification of control tasks at primary production level to be carried out by voluntary partnerships (e.g. production co-operative).

Compliance of animal

production and conditions

• Depending on the common strategy of production or common goal of partnership.

:

Table 11: Identification of general obligations and control tasks at primary production level to be carried out by the competent authority.

General obligations • Controls taking account of identified risks associated with animals, feed or food, feed or food businesses, the use of feed or food or any process, material, substance, activity or operation that may influence feed or food safety, animal health or animal welfare;

• Feed or food business operators' past record as regards compliance with feed or food law or with animal health and animal welfare rules;

• The reliability of any own checks that have already been carried out;

• Any information that might indicate non-compliance.

Control activities • Examination of any control systems that feed and food business operators have put in place and the results obtained;

• Inspection of: o Primary producers' installations, including their surroundings,

premises, offices, equipment, installations and machinery, transport, as well as of feed;

o Cleaning and maintenance products and processes, and pesticides;

• Checks on the hygiene conditions;

• Assessment of procedures on good hygiene practices (GHP), good farming practices and HACCP;

• Examination of written material and other records which may be

• relevant to the assessment of compliance with feed or food law;

• Interviews with food business operators and with their staff;

• The reading of values recorded by feed or food business measuring instruments;

• Any other activity required to ensure that the objectives of legislation are met.

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Annex 2. Controls – Transport


Table 12: Characterisation of control types during transport to be carried out by the transporter or attendant.

Type Internal control

Carried out by Attendant, the person who accompanies the animal during a journey and directly

is in charge of animal welfare

Tasks (Self-) control of compliance with animal welfare, transport and hygiene rules

Frequency Every single day when animals are transported to a slaughterhouse

Location During the whole transport route (from holding of origin / assembly centre to

slaughterhouse)

Table 13: Characterisation of control types during transport to be carried out by the competent authority.


Carried out by Official veterinarian or any veterinarian designated for this purpose by the

competent authority

Tasks Animal welfare related inspection tasks; check that the requirements of

Regulation (EC) 1/2005 have been complied with, by carrying out non-

discriminatory inspections of animals, means of transport and accompanying

documents

Frequency The journey log is to be inspected before any long journey at the place of

departure. Livestock vessels are to be inspected before any loading of animals.

Other specified checks can take place at any stage of a long journey on a random

or targeted basis

Location At holding of origin, assembly centres, control posts or at the slaughterhouse

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B.) Identification of control tasks carried out before or during transport

Table 14: Identification of control tasks during transport to be carried out by the transporter.

General • That animals are not transported in a way likely to cause injury or undue suffering to them.

Handling • Handling of animals without causing unnecessary distress during collection and transport.

Vessel • Means of transport, containers and their fittings are designed, constructed, maintained (cleaning and disinfection, etc.) and operated in compliance with legislation.

Compliance • Compliance of space allowance, surface, bedding, ventilation, feed and water supply with legistical requirements.

Time limits • Time limits for watering, feeding and milking intervals, journey times and resting periods are kept.

Record keeping • Keeping of register with information on animals, disinfection, duration of transport and transport route.

Health status • No contact between animals of a lower health status and the consignment or animals at any time, between leaving the holdings or the assembly centre of origin and arriving at their destination.

Table 15: Identification of control tasks during transport to be carried out by the competent authority.

Vessel • Livestock vessel is built and equipped for the number and the type of animals to be transported;

• Compartments where animals are to be accommodated remain in a good state of repair;

• Equipment remains in good working order.

Time limits • Declared journey times are realistic

Fitness of animals • Animals are fit to continue their journey

Loading/unloading • Loading/unloading operations are being carried out in compliance with legislation

Feed and water • Feed and water arrangements are in accordance with legislation

Record keeping • Transporters indicated in the journey log have the corresponding valid transporter authorizations;

• Validity of certificates of approval for means of transport and for competence for drivers and attendants; valid health certificate;

• Journey log submitted by the organizer is realistic and indicates compliance with this Regulation

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Annex 3. Controls – Slaughterhouse


Table 16: Characterisation of control types at slaughterhouse level to be carried out by the food business operator.

Type Internal control

Carried out by Owner and staff of the establishment, e.g. animal welfare officer

Tasks (Self-) control of good hygiene practice, good manufacturing practice, HACCP,

quality management, animal welfare, ect.

Frequency Every single day when animals are slaughtered

Table 17: Characterisation of control types at slaughterhouse level to be carried out by the competent authority.


Carried out by Official veterinarian, approved veterinarian or official auxiliary

Tasks Examination and inspection tasks follow a detailed protocol laid down in Annex IV

of Regulation (EC) 1009/2009 (in regard to animal welfare) and Annex I of

Regulation (EC) 854/2004 (inspection tasks)

Frequency Every animal is to be inspected

B.) Identification of control tasks carried out at the slaughterhouse

Table 18: Identification of control tasks at slaughterhouse level to be carried out by the food business operator.

Objectives of HACCP-based

procedures

• Proper identification of animal;

• Presence of relevant food chain information of animal;

• That animal does not come from a holding or an area subject to a movement prohibition or other restriction for reasons of animal or public health, except when the competent authority so permits;

• Cleanliness of animal;

• Health status of animal, as far as the food business operator can judge;

• Satisfactory state of animal as regards welfare on arrival at the slaughterhouse.

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Animal welfare • Prevention of any avoidable pain, distress or suffering during their killing and related operations;

• Physical comfort and protection of animals, in particular by being kept clean in adequate thermal conditions and prevented from falling or slipping;

• Protection of animal from injury;

• Handling and housing of animals taking into consideration their normal behaviour;

• Presence of signs of avoidable pain or fear or exhibited abnormal behaviour;

• Feed or water;

• Prevented from avoidable interaction with other animals that could harm their welfare.

Hygiene of foodstuffs

• Compliance with microbiological criteria for foodstuffs;

• Procedures necessary to meet targets set to achieve the objectives laid down in legislation;

• Compliance with temperature control requirements for foodstuffs;

• Maintenance of the cold chain.

Other controls to be carried out

according to multiple legislative

texts

• Sampling and analysis;

• Competence, training and health of staff handling foodstuffs;

• Personal hygiene and protective cloths of staff;

• Pest control;

• Storage and handling of waste;

• Results of any relevant analyses carried out on samples taken from animals or other samples that have importance to human health;

• Cleaning and disinfection of any facilities used to store and handle carcases;

• Good condition of facility;

• Facility allows performance of all necessary inspection tasks and any other required operations taking place at the slaughterhouse;

• Drainage facilities;

• Prevention of (cross-)contamination of animals;

• Prevention of (cross-)contamination of meat

• Separation in space or time of all operations carried out during slaughter;

• Slaughter hygiene.

Table 19: Identification of control tasks at slaughterhouse level to be carried out by the competent authority..

Food chain information • Check and analyse relevant information;

• Check any accompanying official certificates and declarations made by veterinarians carrying out controls at the level of primary production;

Ante-mortem inspection • Check if animal welfare has been compromised;

• Presence of any condition which might adversely affect human or animal health;

• Clinical inspection of animals put aside;

• (Emergency slaughter is not included in this analysis).

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Animal Welfare • Verification of compliance will relevant Community and national rules on animal welfare, e.g. protection of animals at the time of slaughter (Reg. (EC) 1099/2009) and during transport (Reg. (EC) 1/2005).

Post-mortem inspection • A detailed overview of ante & post-mortem inspection tasks at the slaughterhouse is presented in Tab. 1. ;

• Whenever considered necessary, obligatory examination can be supported by additional tasks, such as palpation and incision of parts of the carcase and offal and laboratory tests: o To reach a definitive diagnosis; or o To detect the presence of:

• An animal disease,

• Residues or contaminants in excess of the levels laid down under Community legislation,

• Non-compliance with microbiological criteria, or

• Other factors that might require the meat to be declared unfit for human consumption or restrictions to be placed on its use,

• In accordance with point 2 of Part B of Chapter IV of Section IV of Annex I to Regulation (EC) 854/2004, the competent authority may limit the post-mortem inspection procedures of fattening pigs to a visual inspection, provided that the following conditions are complied with the requirements listed in Annex II of Regulation (EC) 1009/2009 and Annex VIb of Regulation (EC) 2074/2005. As risk-based meat inspection in fatteners is at present not carried out in the UK, these inspection tasks are not mapped in detail.

Specified risk material and other

by-products

• Check that specified risk material is handled and disposed of in accordance with legislation;

• Verification of the correct application of rules set out in Reg. (EC) 999/2001 and assurance that measures are taken to avoid any contamination in slaughterhouses.

Laboratory testing • Verification of compliance with the rules and criteria laid down in legislation in respect to microbiological criteria o Aerobic colony count; o Enterobacteriaceae; o Salmonella;

• Examination for Trichinella infestation in carcases of domestic swine;

• TSE testing – depending on surveillance sub-population, age-category and sampling rules set out in national program.

• Detection of unauthorised substances or products, control of regulated substances;

• Detection of OIE list A and, where appropriate, OIE list B diseases,

• Any other necessary laboratory testing.

Other tasks • The official veterinarian will take account of results of audits carried out to verify food business operator’s compliance with legal requirements. Additional tasks include o supervision of health marking, o communication of inspection results and o decision making concerning live animals, animal welfare

and meat

MC1003 – Report N.3 2010


Table 20: Meat inspection tasks according to Regulation (EC) No 854/2004. (Optional = in the discretion of the meat inspector. "When necessary").

SHEEP CATTLE PIGS

Young** Old

Obli-

gatory

Opt-

ional

Obli-

gatory

Opt-

ional

Obli-

gatory

Opt-

ional

Obli-

gatory

Opt-

Ional

ANTE-MORTEM V

V

V

V

PO

ST

- M

OR

TE

M I

NS

PE

CT

ION

WHOLE CARCASE External surface V

V

V

V

HEAD

Head, mouth, throat

etc. V*

V

V

V

Retropharyngeal LNN

V* I

I

Submaxillary LNN

I

I

Parotid LNN

V*

I

Maseter muscles

I

Tongue

V* P

V + P

V

LUNGS

Parenchyma V+P I V + P

+I*

V + P

+I* V + P+I*

Trachea V I V + I*

V + I*

V+I*

Major bronchi

I*

I*

I*

Mediastinal LNN P I I

I

P

Bronchial LNN P I I

I

P

OESOPHAGUS V I V

V

V

HEART Heart V I V + I

V + I

V + I

Pericardium V

V

V

V

DIAPHRAGM V

V

V

V

LIVER

Parenchyma V + P +

I V + P I

V + P +

I V+P

Hepatic LNN (=portal) V + P

V + P I V+P

V+P

Pancreatic LNN V

V

V+P

V

GI TRACT

Stomach and intestines V

V

V

V

Mesentery V

V

V

V

Gastric LNN V

V + P I V + P I V + P I

Mesenteric LNN V

V + P I V + P I V + P I

SPLEEN V P V P V P V P

KIDNEYS Parenchyma V I V I V I V I

Renal LNN

I

I

I

I

GENITALS and

assoc. Organs

Uterus V

V

V

Udder V

V (P+I)* V

Supramammary LNN V

V (P+I)* (V+I)***

PLEURA V

V

V

V

PERITONEUM V

V

V

V

UMBILICAL AREA (V+P)** I** V+P I

(V+P)** I**

JOINTS (V+P)** I** V+P I

(V+P)** I**

V: visual inspection, P: palpation, I: incision

* not required if organs are not destined for

human consumption

**only in young animals (Bovines: <6wks old)

***only in sows

Annex 4:

MC1003 – Report N.3 2010




Project MC1003


and

assessment of the benefit to public and animal health of post-mortem

inspection of green offal in red meat species at slaughter

Project Report N.4 – Creation and validation of a tool for the assessment of the effectiveness of meat inspection tasks

Authors: Nikolaos Dadios, Research Assistant

Silvia Alonso, Lecturer in Veterinary Public Health


Neville Gregory, Professor of Animal Welfare Physiology


2

1. EXECUTIVE SUMMARY

Background

Meat inspection (MI) in the abattoir is an important component in the process of

protecting consumers from meat related hazards. It consists of a series of steps of

inspection of the live animal, the carcase and its organs with the aim of detecting,

identifying and removing pathological findings. Nowadays, in more economically

developed countries, the main threat to public health (PH) from meat consumption

comes from hazards that do not cause obvious disease or clinical signs in the animal

or the carcase. In light of this, it has been argued that the traditional MI system is not

the most appropriate method to detect and control these hazards. In addition, some

of the obligatory MI practices, like the incision of organs and lymph nodes (LNs),

may be even contributing to cross-contamination of carcases potentially aggravating

the problem. Eliminating MI tasks that do not greatly contribute to the detection of

hazards would free resources that could be used elsewhere for the control of

meatborne diseases. In order to do this, an objective evaluation of the true

effectiveness of all MI tasks in relation to the most prominent hazards is needed.

Aims and objectives

The aim of the work presented in this report was the development of a computer

based model for the qualitative assessment of the effectiveness of meat inspection

tasks to detect hazards associated with meat production (i.e. capacity of detection of

hazard).

Approach

With the objective of identifying the essential elements that should be part of an MI

effectiveness assessment tool, a workshop was organised with all project team

members (including international partners) and representatives from the Food

Standards Agency (FSA). On the basis of the workshop outcome, a tool was

developed that measures the effectiveness of each MI task to detect a particular

hazard as a combination of sensitivity (Se) and positive predictive value (PPV). These

are two common parameters used to characterize diagnostic tests in, among others,

animal and human medicine. The model produces, for each MI task, a score out of

five categories (very low, VL; low, L; medium, M; high, H; very high, VH) that

represents the task’s capacity to detect a given hazard.

3

The model has been tested on a selection of seven hazards, including public health

(PH), animal health (AH) and animal welfare (AW) hazards.

Outcome/Key Results Obtained

On initial validation, the tool showed a good discriminatory capacity (between

effective and ineffective tasks), which ensures that appropriate relative

comparisons of effectiveness among MI tasks can be drawn from the model

outputs. Further validation of the model with a greater number of hazards would

be needed to confirm the suitability of the model output for a greater range of

situations. Nevertheless, the results obtained to date are promising and further

work should be encouraged.

Not surprisingly, the model validation demonstrated that the current MI system as

a whole is most effective at detecting those hazards that cause either pathognomic,

macroscopic or multisystemic lesions. Across the range of hazards tested as part of

this project, the most effective MI tasks (higher scoring) were visual inspection of

the intestines, followed by ante mortem and whole carcase inspection. The hazard

that could be detected by most MI tasks was classical swine fever in pigs.

The lack of reliable data and information needed to inform the model represents

the greatest constraint encountered in this project. It will require a substantial

amount of field-based research to obtain more precise data. Once this is available,

the tool will be a very solid and valuable instrument in the evaluation of MI tasks.

4

2. GLOSSARY

AH Animal Health

AM Ante-mortem inspection

AW Animal Welfare

C Cattle

CD Capacity of detection

CSF Classical Swine Fever

FSA Food Standards Agency

GO Green offal

LNs Lymph nodes

MAP Mycobacterium avium spp. paratuberculosis

MHS Meat Hygiene Service

MI Meat inspection

MIs Meat Inspectors

OV Official Veterinarian

P Pigs

PH Public Health

PM Post-mortem inspection

PPV Positive Predictive Value

S Sheep

Se Sensitivity of a MI task

Sp Specificity of a MI task

TB Tuberculosis

VLA Veterinary Laboratories Agency

5

Contents

1. EXECUTIVE SUMMARY ............................................................................................... 2

2. GLOSSARY ....................................................................................................................... 4

3. BACKGROUND............................................................................................................... 6

4. MATERIALS AND METHODS ..................................................................................... 8

4.1 Definitions and reference populations .............................................................................. 8

4.2 Description of the model ..................................................................................................... 9

4.2.1 Model parameters ........................................................................................................ 10

4.2.2 Conversion of Se and PPV to qualitative scores............................................................ 11

4.2.3. Final task score .............................................................................................................. 12

4.3 Model validation ............................................................................................................... 13

4.3.1 Selection of hazards ...................................................................................................... 13

4.3.2 Collection of data and information ............................................................................... 14

4.3.3 Model revision .............................................................................................................. 16

5. RESULTS ......................................................................................................................... 17

6. DISCUSSION .................................................................................................................. 22

7. ACKNOWLEDGEMENTS ........................................................................................... 24

8. REFERENCES ................................................................................................................. 25

9. ANNEX ........................................................................................................................... 27

6

3. BACKGROUND

Today, Campylobacter, Salmonella, Yersinia and Escherichia coli O157 are among the

most important meatborne pathogens causing human disease (EFSA, 2010). These

hazards are usually transmitted through faecal or cross-contamination to the carcase

during the slaughter process and generally do not cause clinical signs or obvious

lesions in infected animals (Snijders and van Knapen, 2002). As a result, these

hazards are virtually undetectable with the current meat inspection (MI) system,

which relies on the detection of macroscopic lesions in the carcase and organs. In

addition, some MI tasks may even aggravate the problem by contributing

unnecessarily to the cross-contamination of carcases. In this context it has been

argued that the MI system as a whole, and some MI tasks in particular, are not fit for

purpose anymore and should be overhauled by more suitable mechanisms to

address the current threats to human health (Snijders and van Knapen, 2002, Berends

et al., 1996). Eliminating tasks that do not contribute in any substantial way to the

detection of hazards would free resources that could be used elsewhere for the

control of meatborne diseases (Edwards et al., 1997). Nevertheless, in order to do

this, it is necessary to objectively assess to what extent each current MI task

contributes to the protection of animal health, animal welfare and public health.

This report presents the development of a computer based model to objectively

assess the effectiveness of the MI tasks in relation to specific hazards. In the context

of this project ‚effectiveness‛ is understood as the ‚capacity of a MI task to detect a

specific hazard‛, be it a hazard to human health, animal health and animal welfare.

This report includes a description of the basic principles underlying the model and

the results of a validation study with a specific number of hazards.

The tool allows the relative comparison of effectiveness among MI tasks for each

specific hazard and the identification of those tasks that contribute most to the

detection of hazards.

The activities presented in this report are separated in two parts: The first part

consisted of the organisation and delivery of a workshop with project partners, to

discuss the parameters underlying the tool. The workshop outcomes, including the

description of the model parameters, are described in detail in report N.2. The second

part was the development of an effectiveness evaluation tool based on the outcomes

7

of the workshop. Finally we carried out an initial validation of the model on seven

hazards.

8

4. MATERIALS AND METHODS

4.1 Definitions and reference populations

The population of reference in our model is the ‚population of animals that are

infected with (or carry) a hazard‛ (population of infected animals, P). Therefore, the

effectiveness score produced by the model indicates the capacity of a MI task to detect a

hazard in infected animals. The subpopulations of relevance in the model are described

in figure 1.

Figure 1 – Sub-populations of relevance in the model

where,

P = Animals infected with/carrying a hazard

p₀ = Proportion of infected animals that show clinical signs/lesions.

p₁ = the proportion of p₀ animals with lesions in a particular organ

p₂ = the proportion of p₁ animals that are detected by the MI task

As described in detail in report N.2 of project MC1003, the effectiveness of a meat

inspection task can be defined by two parameters:

Sensitivity (Se) = the ‚ability of the task to correctly detect infected animals WITH

lesions‛ or “the proportion of infected animals WITH LESIONS that are identified by the

task as infected‛(Fletcher and Fletcher, 2005). In this project, the formula describing Se

is:

Se = p₁*p₂

9

Positive Predictive Value (PPV) = the ‚probability that a sample (carcase) identified

as positive by a task is truly positive‛ (Fletcher and Fletcher, 2005) (MacMahon and

Trichopoulos, 1996). The formula describing PPV is:

PPV = (p₀*Se)/*(p₀*Se) + (1-p₀)(1-Sp)

where,

Sp = Specificity, the ‚ability of a task to identify animals without lesions‛ or

“the proportion of animals without lesions that are identified by a task as negative‛.

Sensitivity alone does not give a clear indication of how effective a task is at

detecting a hazard, because the effectiveness of a test (e.g. meat inspection task) is

also influenced by the prevalence of the hazard in the tested population. Therefore,

irrespective of sensitivity, the likelihood that a task will detect a hazard is greater if

the hazard is more prevalent in the population..

The PPV value increases as the prevalence increases, i.e. the proportion of rejections

that are unnecessary will be lower. It follows that the effectiveness of a task increases

with the prevalence of a condition/hazard in a population.

The relationship between the parameters described in this paragraph, is presented

in table 1.

Table 1 – Se, Sp and PPV

HAZARD

PRESENT

HAZARD

ABSENT TOTALS

TEST POSITIVE a b a + b

TEST NEGATIVE c d c + d

TOTALS a + c b + d a + b + c + d

Se = a/a+c; Sp = d/b+d; PPV = a/a+b

4.2 Description of the model

The model (available as a separate file: ‚Model.xls‛) combines, for each meat

inspection task, the estimates of Se and PPV relative to a specific hazard. The final

qualitative estimate falls in one of five categories: very low (VL), low (L), medium

10

(M), high (H) or very high (VH) effectiveness. See annex 1 for a representation of the

model process.

4.2.1 Model parameters

The list of model input parameters can be seen in figure 2.

Figure 2 – Representation of model input parameters (green)

Parameters p₀, p₁ and p₂ are obtained from published literature, databases and/or

expert opinion. Parameters in red font are automatically calculated by the model. Se

is obtained through p₁ and p₂ and PPV through p₀, Se and Sp, as described

previously.

Specificity (Sp) was entered as a fixed value for all the tasks/hazards; it is very

unlikely that organs without lesion will be identified as having a lesion and rejected;

in other words, it is very unlikely for an inspector to declare an organ or carcase

positive for a particular hazard when there are no lesions on the organs. In addition,

it was assumed that there is a very low likelihood of misclassification of other

diseases (i.e. organs/carcases carrying a different hazard being incorrectly identified

as carrying the hazard of interest). In light of this, and according to the definition of

Sp in this project (see above) it was decided that a Sp=0.99 is a realistic estimate for

all hazards/tasks considered. To validate this assumption, the PPV values obtained

through expert elicitation for a number of tasks/hazards were compared with the

PPV values computed by the model for the same tasks/hazards when using Sp =

0.99. The results showed a very good correlation between the two PPVs for the pig

conditions studied, supporting the choice of specificity used in the model. The

correlation was weaker for hazards related to sheep and cattle; nevertheless, only

one expert contributed information on these species as it was not possible to recruit a

11

second expert, therefore the results of this validation can only be partially assessed.

The results of the validation are reported in annex 2.

4.2.2 Conversion of Se and PPV to qualitative scores

After computing Se and PPV parameters in the model they are converted into

qualitative estimates. Specifically, on the basis of their numerical value, they are

converted to one of five qualitative score categories, ranging from very low (VL) to

very high (VH). This was done by defining a numerical range for each qualitative

category. Each Se and PPV figure is then assigned to one of the ranges.

The model differentiates between two main types of meatborne hazards: (i) hazards

that may not (or rarely) cause visible lesions and, if they do so, they are not

accompanied by characteristic, macroscopical findings (‚micro-hazards”) – hazards

typical of this group are Campylobacter, Toxoplasma and Salmonella; and (ii) hazards

typically accompanied by obvious and characteristic macroscopical findings (‚macro-

hazards”) – hazards like M. bovis, Cysticercus spp and Fasciola hepatica fall into this

category. The qualitative scoring for both these types of hazards is different (see

table 2). The sensitivities for macro-hazards are higher than for the micro-hazards,

PPVs are also higher as they are partially dependent on Se. As the qualitative score

describes relative performance, a high sensitivity (or PPV) for a micro-hazard would

be relatively low for a macro-hazard, therefore a different scale is required to

qualitatively describe relative performance for micro- and macro-hazards.

12

Table 2 - Qualitative categorization for Se and PPV

The decision on the appropriate categorization of parameters (as described above),

was made by four members of the research team in two separate workshops. The

most important aspects considered by the project members were that the ranges:

should be realistic and sensible (i.e. a sensitivity for a given hazard defined in

categorization as high should be in agreement with the most prevailing

opinion in the expert community)

should provide adequate power of discrimination for the comparison of tasks.

4.2.3. Final task score

In the model, the combination of the qualitative categories of Se and PPV parameters

produces a final effectiveness score (from VL to VH). Discussion among team

members was the basis for the Se/PPV combination matrix finally integrated in the

model (see table 3 for details of the matrix).

HAZARD CATEGORIES

Se

VL L M H VH

Micro -Hazards

≤0.01 >0.01 – 0.05 >0.05 – 0.1 >0.1 – 0.25 >0.25

Macro -Hazards

≤0.1 >0.1 – 0.25 >0.25 – 0.5 >0.5 – 0.75 >0.75

PPV

VL L M H VH

Micro -Hazards

≤0.01 >0.01 – 0.05 >0.05 – 0.1 >0.1 – 0.25 >0.25

Macro -Hazards

≤0.1 >0.1 – 0.25 >0.25 – 0.5 >0.5 – 0.75 >0.75

13

Table 3 – Final task effectiveness scores

Sensitivity is an indicator of false negatives (i.e. the proportion of infected carcases

with lesions that are not identified), while PPV is an indicator of the proportion of

detected carcases that are false positives, i.e. unnecessary rejections. This in turn

means that Se is of greater PH, AH and AW importance (i.e. lower Se means that

more positive carcases are not detected by the task, with any consequences this may

have on PH, AH or AW) and PPV of greater economic/financial. This important fact

was taken into account when designing the final score matrix; Se was given greater

weight towards the final score than PPV. The aim was to reflect that the primary

purpose of a MI task is to safeguard PH, AH and/or AW.

For each hazard, the final score produced by the model for one inspection task is

directly comparable to the score of other inspection tasks along the slaughter line

allowing for the relative ranking of inspection tasks in relation to their capacity to

detect the given hazard. The score can also be compared to the score obtained for the

same inspection task in relation to any other hazards of the same category

(micro/macro).

4.3 Model validation

4.3.1 Selection of hazards

In order to test the model a number of hazards were selected and applied to the

model. A selection of seven hazards was made in consultation with the Food

Standards Agency (FSA). The aim was to achieve the best possible representation of

PPVSensitivity

VL L M H VH

VL VL VL L M H

L VL L M H H

M VL L M H VH

H L M H H VH

VH L M H VH VH

14

hazards in relation to species, risk categories, pathological findings, prevalence in

the UK, ability to multiply on the carcase and detection capacity in green offal (as

required by objective 4 of project MC1003, see report N.5 for details). The objective

was to test the model in the broadest possible range of conditions in order to expose

any eventual weaknesses and limitations. Selected hazards and their characteristics

are presented in table 4.

Table 4 – List of selected hazards for validation

4.3.2 Collection of data and information

To obtain the required input parameters for the model we consulted several sources

of information. In the first instance, scientific literature and databases of various

agencies and public bodies (mainly FSA and VLA) were consulted. When data gaps

were identified, information was collected via expert elicitation and, if this step

failed to provide the required data, the opinion of the project members was

incorporated, based on their collective knowledge and experience. A full list of the

databases, reports and scientific literature used in the testing of the tool can be seen

in Annex 3.

Whenever the figures reported in two or more sources were found to be conflicting

or incompatible a prioritisation process was implemented. The criteria for this

process were, in ranking order:

source referring to UK

source referring to Europe

date

relevance of properties of animals referred to (species, age of animals, sex etc.)

HAZARD Species RiskCategory

Endemic/Notifiable

Single / Multiple sites

Growthon carcase

Lesions in GO

M. bovis Cattle AH E M NO YES

MAP Cattle AH E M NO YES

TOXOPLASMA Sheep PH E M NO YES

SALMONELLA Pigs PH E M YES YES

CSF Pigs AH N M NO YES

HERNIAS Pigs AW E S NO YES

TAIL BITING Pigs AW E S NO NO

15

Expert opinion consultation

Up to two experts were identified for both ante-mortem and post-mortem inspection

and for each animal species of interest – cattle (C), sheep (S) and pigs (P). The experts

for AM were Official Veterinarians (OVs) while for PM were meat inspectors (MIs)

currently working in UK abattoirs.

Further selection criteria were, first, the experts’ experience (see table 5 for details on

the experience requirements) in the hazard of interest and, secondly, their

willingness to participate in the project.

Table 5 – Experts’ selection; Minimum experience requirements

Identified candidates were approached and invited to participate in the expert

elicitation. Given the fact that many abattoirs in the UK that slaughter large numbers

of sheep also process many cattle, the same experts were used for both animal

species.

The abattoirs where experts were employed are all located in the south of England

but receive livestock from across the UK. Their production throughput is medium to

high (i.e. >3,000 sheep/wk, >200 cattle/wk, >5,000 pigs/wk). The characteristics of the

animals slaughtered can be considered as representative for the UK as a whole. The

profiles of the six selected experts are provided in annex 4.

The expert elicitation was done through a modified Delphi technique. Briefly, a first

round of data gathering was run by individual questionnaires sent to experts via

email. After that, data from experts were collated. A second elicitation round was

run via email and/or telephone call in order to clarify some of the experts’ responses

or reach consensus when disagreements on estimates were found. Finally, final

estimates were calculated.

POSITION YEARS OF SERVICE ANIMALS INSPECTED

ANTE MORTEM 5 years PIGS – 0.8 millionSHEEP – 0.5 million

CATTLE – 0.05 million

POST MORTEM 10 years PIGS – 3 millionSHEEP – 1 million

CATTLE – 0.2 million

16

Data from meat inspection on Classical Swine Fever (CSF) are not available in the

UK, since the disease is not endemic in the country and there is no experience with

slaughter of infected animals in abattoirs. To obtain the necessary data scientists

working in EU laboratories dealing specifically with CSF (e.g. reference laboratories)

were invited to participate. These experts had knowledge of post mortem details and

frequency of findings of the disease in certain countries. This information was then

extrapolated to the MI process in the abattoir environment (see notes in CSF sheet,

file ‚Model with data.xls‛). A list of CSF experts can be seen in Annex 4.

The protocol for the extraction of data from questionnaires from two different

experts can be seen in Annex 5.

4.3.3. Model revision

The model, together with supporting documentation, was sent to the international

partners for revision (Lis Alban, Danish Agriculture & Food Council, Denmark;

Lueppo Ellerbroek, Food Institute for Risk Analysis, Germany). They were asked for

their general feedback and to comment specifically on:

the correctness of the assumptions in the model

the presence of any obvious mistakes

the clarity of the model

the scoring system and, in particular, its discrimination capacity

the ranges for the categorisation of Se and PPV

17

5. RESULTS

The feedback of the international partners on the model was positive. The finalized

model is provided as a separate file (Model.xls) including all relevant notes and

instructions.

The results of the validation for all MI tasks and all considered hazards can be

viewed in detail in the separate file ‚Model with data.xls‛. Table 6 presents a

summary of the results.

Table 6 – Selected hazards and MI tasks effectiveness scores

* VL: very low; L: low; M: medium; H: high; VH: very high ‚capacity of detection‛.

Capacity of detection of Mycobacterium bovis (TB) in cattle by MI tasks

The results of the model show that three MI tasks have a solid detection capacity

with regard to M. bovis in cattle: these are the inspection of the mediastinal LNs

(detection capacity high), the retropharyngeal LNs (detection capacity medium) and

the bronchial LNs (detection capacity medium). Considering the failure rate of the TB

farm surveillance tests [average Se 90%, (de la Rua-Domenech et al., 2006)] and the

number of TB slaughterhouse cases (i.e. carcases found with TB lesions in animals

that were not reactors) found in the UK abattoirs during routine meat inspection, a

CATTLE CATTLE SHEEP PIGS PIGS PIGS PIGS

TB MAP Toxoplasma Salmonella CSF Hernias Tail biting

VL VL VL L H VH VH

VL M L VL VH VL VH

HEAD Mouth, tonsils etc. VL H

Retrophar. LNs M

Submaxillary LNs VH

Parotid LNs VL

LUNGS Parenchyma VL VL VH

Mediastinal LNs H VL

Bronchial LNs M

SPLEEN L VH

HEART Myocardium L

Pericardium M

LIVER Parenchyma (& bladder) L H

KIDNEYS Parenchyma L VH

GI SYSTEM Stomach and intestines H L VH VH VH

Gastric LNs VL

Mesentery M VL

Mesenteric LNs VL M VL VL H

PLEURA VH

PERITONEUM M H

WHOLE CARCASE and external surfaces

LIVE ANIMAL - Ante mortem

Organ

18

significant number of infected animals could be missed if they were not detected by

MI. Some of these animals originate from farms not previously identified as TB

infected. Assuming that early detection is imperative for the success of the control of

the hazard on farm and within the national herd, these three MI tasks do make an

important contribution.

There are six more tasks that literature suggests can play a role in the detection of the

disease: ante-mortem inspection, inspection of the whole carcase, inspection of the

mouth and tonsils, parotid LNs, parenchyma of the lungs and mesenteric LNs. The

model indicates a very low capacity of detection of these tasks, due primarily to the

low frequency with which lesions associated with M. bovis are found in the organs

and tissues inspected by these tasks.

Capacity of detection of Mycobacterium avium subsp paratuberculosis in cattle

Mycobacterium avium subsp paratuberculosis (MAP) can be detected by five MI tasks:

the ante mortem inspection, the visual inspection of the whole carcase and the three

inspection tasks of GO (i.e. visual inspection of the intestines and the mesentery and

palpation of the mesenteric LNs). The contribution of the GO inspection, in

particular the inspection of the intestines (score high), to the detection of MAP is not

surprising given that those organs are the target location for the pathogen in infected

animals, causing very characteristic lesions. The relatively high score (medium) of the

whole carcase visual inspection (looking for emaciation) in the detection of MAP

was more surprising, because it is a finding that is common to many other chronic

diseases and conditions (e.g. old age). It is however very easy to detect and,

according to an external expert, an animal with emaciation ‚should not be missed‛

(Annex V.2.1.ii). Therefore, it is expected that a large proportion of animals with

lesions will be detected by this specific MI task and this, together with the relatively

high proportion of infected animals showing pathological findings (i.e. high p₀

value), will result in a final medium effectiveness score. Ante mortem inspection

contributes to a much smaller degree to the detection of the hazard (score very low),

due primarily to the low sensitivity of the task in relation to this hazard.

Capacity of detection of Toxoplasma gondii in sheep

19

Toxoplasma gondii is very widespread among the sheep population in the UK, like in

many other European countries. It is primarily associated with abortions in ewes

and, rarely, with disease in lambs. The disease is usually multi-systemic but with

very mild and non specific signs and lesions (Radostits, 2000). This means that at MI

the hazard can easily be missed (low Se), while its lesions can be confused with those

of other hazards, usually parasites. The nature of this hazard is reflected in the

results of the model, where there are many MI tasks with a theoretical potential for

detection, although no MI task scored higher than low. Nevertheless considering the

large amount of small ruminants being slaughtered in the UK per year, a MI task

with a low or very low capacity of detection (in relative terms) would still contribute

to the detection of a substantial number of positive animals in the country (in

absolute terms).

Capacity of detection of Salmonella Typhimurium in pigs

Salmonella Typhimurium is the major Salmonella serotype that causes disease in

humans through pig meat consumption. Pigs are normally carriers of the hazard

(colonization happens usually before slaughter age) but very rarely show clinical

signs. The typical disease picture is enterocolitis and, very rarely, septicaemia. For

this reason the evaluation of this hazard dealt only with the typical (enterocolitis)

form of the disease.

Salmonella can be detected by five tasks. Of them, whole carcase inspection, gastric

LNs inspection and mesenteric LNs inspection had a very low score while ante

mortem inspection produced a low score. The most effective task is, as expected, the

inspection of the intestines (very high). This last score is explained by the fact that, an

animal showing signs of Salmonella infection is highly likely to present clinical signs

in this particular organ; effectively the only expression of salmonella in pigs is

enterocolitis (Straw, 1999).

The results for Salmonella indicate that the inspection of the intestines plays a very

important role in the identification of organs that may carry this pathogen. However,

it is important to point out that the real risk to human health does not come from the

diseased animals (or animals with lesions), which constitute only a very small part of

the infected animal population, but from the faecal contamination of the carcases

during the slaughter process whenever subclinically infected animals are

slaughtered. Salmonella on those carcases cannot be detected by any MI task. Faecal

20

contamination of the carcase is frequently used as a proxy for potential

contamination with Salmonella. This aspect was beyond the scope of this work and

has not been addressed in this project.

Capacity of detection of Classical Swine Fever (CSF) in pigs

CSF is the hazard for which the MI system as a whole showed the greatest capacity

of detection; most MI tasks scored higher than VL and, in addition, it includes more

tasks scoring H and VH than for the other hazards.

The explanation for this lies in the fact that in non-endemic countries, like the UK,

where the entire pig population is fully susceptible to this virus, the majority of

animals that get infected are likely to develop clinical signs (lesions). In addition, the

clinical and pathological picture of this disease is severe. A diseased animal is

unlikely to go undetected during MI. The hazard also attacks many organs and other

parts of the body and so it can be detected by many MI tasks. This means that,

considering the number of pigs slaughtered in big commercial abattoirs and the

variety of farms and regions they originate from, and also the difficulty of detection

of the disease on the farm by clinical inspection, MI in abattoirs can act as a very

effective surveillance tool for the early detection of the disease.

Capacity of detection of umbilical hernias in pigs

There are two most frequent types of hernias observed in pigs: umbilical and

inguinal. This part of the project deals only with the former ones, given that it is

more frequent, affects equally both males and females and it is more likely to be

identified at post-mortem inspection. On the slaughter line, all umbilical hernias are

removed from carcases at evisceration. The structures related with hernias (skin,

connective tissues etc.) are attached to, and follow, the green offal (GO) and can be

seen during GO MI. It follows that the most important MI task for the detection of

hernias are likely to be the GO inspection. Also, a significant proportion of the

hernias are accompanied by peritonitis, a secondary complication. The model

indicates that the MI tasks with greater capacity of detection for hernias are the GO

inspection, the inspection of the peritoneum and the ante mortem inspection of

animals in the lairage. The capacity of detection of the hazard through whole carcase

inspection is very low, since hernias have always been removed from the carcase by

21

that stage. The two most important tasks for the detection of this hazard are the AM

inspection and the inspection of the intestines, both scoring VH, while the value of

the inspection of the peritoneum is high (H), mainly related to the remnants of

secondary peritonitis that frequently appear in the abdominal cavity of pigs with

hernia.

Capacity of detection of tail biting in pigs

Signs of tail biting can either be found on the tail or, in more severe cases, in various

other sites on the carcase as a result of metastatic conditions. These conditions are

frequently multiple abscesses in various organs, lymph nodes and parts of the

carcase (e.g. vertebral column). This part of the project deals only with the primary

site lesion and does not take into account the secondary complications as these are

variable both in terms of frequency of appearance and location in the carcase and

organs.

The only two MI tasks with a capacity of detection for tail biting are AM inspection

and whole carcase inspection. Since the condition is external and relatively easy to

detect, the value of these tasks was expected to be high. This was confirmed by the

model, with scores of VH for both inspection tasks. It was surprising, to a degree, to

see that both tasks have the same high score, since it is more difficult at AM

inspection, under lairage conditions, to detect the same proportion of affected

animals compared to the whole carcase post mortem inspection, where every pig is

inspected under good lighting conditions and the carcases have previously been

washed and dehaired.

The value of these two MI tasks, from an AW point of view, is great and they can be

used very effectively for surveillance purposes of AW cases. Moreover, detection of

tail biting contributes also to the protection of public health. This is because many

abattoirs do not routinely split pig carcases along the vertebral column but do so

only when tail biting lesions are found. It is known that even small biting lesions on

the tail can act as entry points for pyogenic bacteria which can cause abscessation

which cannot be detected without carcase splitting (Kritas and Morrison, 2007).

22

6. DISCUSSION

To the best of the authors’ knowledge, this is the first time that a tool for the

assessment of the effectiveness of meat inspection tasks has been created.

The tool developed in this project has the ability to differentiate meat inspection

tasks according to their effectiveness in detecting lesions produced by a particular

hazard. One advantage of the tool is that it is inherently flexible and can be tailored

to the needs of the end user. Thus, the reference population could be the total animal

population, the population of infected animals (like in this case), the population of

infected animals with lesions or just the population of animals in one particular

region. In the same way, Se and Sp could be defined differently. The final result is

that there is an objective estimate of MI tasks that can be used to prioritize inspection

practices at the slaughterhouse.

On validation there was satisfactory discrimination between the tasks in a hazard;

this could be further improved by adapting the ranges of the Se and PPV values.

More accurate and reliable data will lead to better determination of these ranges and,

finally, to better discrimination between tasks.

The results of the validation are generally in agreement with prevailing opinion,

however, the capacity of specific tasks to detect micro-hazards was higher than

expected. It must be noted that the results refer to the population of infected animals

(prevalence =1), not the entire animal population. Also, hazards that cause obvious

and multi-systemic conditions to a great proportion of infected animals, like

septicaemias and viraemias, are detected by a large number of MI tasks and with

high efficiency scores. This underlines the importance of the MI system in the early

detection of these hazards, which are often of epidemic nature and of notifiable

status (e.g. CSF). MI tasks for the detection of conditions that are external and easily

identifiable also scored high (tail biting).

Another interesting finding is that only 20 of the 33 legally required MI tasks were

able to contribute to the detection of the assessed hazards. This would have been

even lower had CSF not been included in the selection. Although only preliminary

conclusions can be drawn from this initial validation, it could nevertheless mean that

across the spectrum of hazards, many MI tasks play a negligible role in hazard

detection. On the other hand, the MI system does not consist of independent but

23

rather ‘interdependent’ and interconnected tasks. It is a very complicated system

and, while it may be possible to measure the performance of a task in separation, it is

more complex to do this in the context of the whole system.

In this model, the most important parameters influencing the final score of a task

were shown to be p₀, p₁ and p₂. The capacity of detection of MI tasks depends on the

frequency with which a hazard produces lesions in infected animals. It is therefore of

paramount importance that the figures for these particular parameters are precise

and accurate.

The main limitation of the tool relates to the need for accurate and reliable data,

which was often lacking. The reliability of the model output depends on the

accuracy of the input figures. Although we used a range of sources of information

for the input parameters and cross-checked information sources, most of the input

parameters were derived from expert opinion. Data is lacking in terms of the

capacity of tasks to identify hazards and more work should be done in order to

improve the reliability of the model outcomes.

24

7. ACKNOWLEDGEMENTS

This project was commissioned and funded by the Food Standards Agency. We want

to thank Bojan Blagojevic and Annette Nigsch, for their invaluable help and

contribution in this project. Special thanks go also to all the external experts that

have participated in this work and their unlimited patience in answering ‚strange‛

questions.

25

8. REFERENCES

BADMAN, R. 2000. Abattoir Monitoring Potential - A study to determine the potential of Gross

Pathology to detect cases of Bovine Johne's Disease in an Abattoir situation when compared with the

ELISA test. National Bovine Johne's Disease Evaluation Animal Health Australia.

BENNETT, R. M. & IJPELAAR, A. C. E. 2003. The Economics of Paratuberculosis (Johne's Disease)

[Online]. University of Reading, UK. Available:

http://www.apd.rdg.ac.uk/AgEcon/livestockdisease/cattle/johnes.htm [Accessed 01.08 2010].

BERENDS, B. R., VAN KNAPEN, F. & SNIJDERS, J. M. 1996. Suggestions for the construction,

analysis and use of descriptive epidemiological models for the modernization of meat inspection. Int J

Food Microbiol, 30, 27-36.

BRADY, C., O'GRADY, D., O'MEARA, F., EGAN, J. & BASSETT, H. 2008. Relationships between

clinical signs, pathological changes and tissue distribution of Mycobacterium avium subspecies

paratuberculosis in 21 cows from herds affected by Johne's disease. Vet Rec, 162, 147-52.

BUERGELT, C. D., HALL, C., MCENTEE, K. & DUNCAN, J. R. 1978. Pathological evaluation of

paratuberculosis in naturally infected cattle. Vet Pathol, 15, 196-207.

CORNER, L., MELVILLE, L., MCCUBBIN, K., SMALL, K. J., MCCORMICK, B. S., WOOD, P. R. &

ROTHEL, J. S. 1990. Efficiency of inspection procedures for the detection of tuberculous lesions in

cattle. Aust Vet J, 67, 389-92.

DE LA RUA-DOMENECH, R., GOODCHILD, A. T., VORDERMEIER, H. M., HEWINSON, R. G.,

CHRISTIANSEN, K. H. & CLIFTON-HADLEY, R. S. 2006. Ante mortem diagnosis of tuberculosis in

cattle: a review of the tuberculin tests, gamma-interferon assay and other ancillary diagnostic

techniques. Res Vet Sci, 81, 190-210.

EDWARDS, D. S., JOHNSTON, A. M. & MEAD, G. C. 1997. Meat inspection: an overview of present

practices and future trends. Vet J, 154, 135-47.

EFSA 2010. The Community Summary Report on trends and sources of zoonoses, zoonotic agents and

food-borne outbreaks in the European Union in 2008 EFSA Journal. European Food Safety Authority.

ELBERS, A. R., BOUMA, A. & STEGEMAN, J. A. 2002. Quantitative assessment of clinical signs for

the detection of classical swine fever outbreaks during an epidemic. Vet Microbiol, 85, 323-32.

ELBERS, A. R., VOS, J. H., BOUMA, A., VAN EXSEL, A. C. & STEGEMAN, A. 2003. Assessment of

the use of gross lesions at post-mortem to detect outbreaks of classical swine fever. Vet Microbiol, 96,

345-56.

FLETCHER, R. H. & FLETCHER, S. W. 2005. Clinical epidemiology : the essentials, Baltimore, Md.,

Lippincott Williams & Wilkins.

http://www.apd.rdg.ac.uk/AgEcon/livestockdisease/cattle/johnes.htm

26

GRACEY, J. F., COLLINS, D. S. & HUEY, R. J. 1999. Meat hygiene, London, W.B. Saunders.

KRITAS, S. K. & MORRISON, R. B. 2007. Relationships between tail biting in pigs and disease lesions

and condemnations at slaughter. Vet Rec, 160, 149-52.

LIEBANA, E., JOHNSON, L., GOUGH, J., DURR, P., JAHANS, K., CLIFTON-HADLEY, R.,

SPENCER, Y., HEWINSON, R. G. & DOWNS, S. H. 2008. Pathology of naturally occurring bovine

tuberculosis in England and Wales. Vet J, 176, 354-60.

MACMAHON, B. & TRICHOPOULOS, D. 1996. Epidemiology : principles and methods, Boston ;

London, Little, Brown.

RADOSTITS, O. M. 2000. Veterinary medicine : a textbook of the diseases of cattle, sheep, pigs, goats

and horses, London, Saunders.

SETH, M., LAMONT, E. A., JANAGAMA, H. K., WIDDEL, A., VULCHANOVA, L., STABEL, J. R.,

WATERS, W. R., PALMER, M. V. & SREEVATSAN, S. 2009. Biomarker discovery in subclinical

mycobacterial infections of cattle. PLoS One, 4, e5478.

SNIJDERS, J. M. A. & VAN KNAPEN, F. 2002. Prevention of human diseases by an integrated quality

control system. Livestock Production Science, 76, 203-206.

STRAW, B. E. 1999. Diseases of swine, Oxford, Blackwell Science.

VLA 2008. VIDA 2008.

27

9. ANNEX

Annex 1. Model process flow diagram

Annex 2. Cross-checks on Sp and PPV values

Annex 3. Sources of data used in the piloting of the model

Annex 4. Experts’ profiles

Annex 5. Protocol for the extraction of data from expert consultation

28

Annex 1 – Model process flow diagram

29

Annex 2 – Cross-checks on Sp and PPV values

PPVs

SPECIES

HAZARD INSPECTION TASK expert

5

expert

6

EXPERTS’

SCORES

(Averages)

Using

Sp .99

Numerical

PPV

(using Sp

.99)

PIGS

CSF

(Micro-H)

LIVE ANIMAL - Ante

mortem 0.50 0.50 VH VH 0.99

WHOLE CARCASE and

external surfaces 0.65 0.60 VH VH 0.99

HEAD Head, mouth,

throat etc. 1.00 0.90 VH VH 0.99

Submaxillary

LNs 1.00 0.90 VH VH 0.99

SPLEEN 1.00 0.95 VH VH 1.00

HEART Pericardium 1.00 0.90 VH VH 0.92

LUNG Parenchyma 0.90 0.95 VH VH 1.00

KIDNEYS Parenchyma 0.99 0.95 VH VH 1.00

LIVER Parenchyma &

bladder 0.99 0.95 VH VH 0.99

GI system Stomach and

intestines 0.90 0.40 VH VH 0.99

PLEURA 0.99 0.95 VH VH 1.00

PERITONEUM 0.99 0.95 VH VH 0.97

HERNIAS

LIVE ANIMAL - Ante

mortem 0.90 0.90 VH VH 1.00

WHOLE CARCASE and

external surfaces N/A N/A

Stomach and intestines 1.00

VH VH 1.00

PERITONEUM 0.99 0.95 VH VH 1.00

TAIL

BITING

LIVE ANIMAL - Ante

mortem 0.90 0.90 VH VH 0.80

WHOLE CARCASE and

external surfaces 0.85 0.95 VH VH 1.00

30

PPVs

SPECIES

HAZARD INSPECTION TASK expert 2 EXPERTS

SCORES

(Averages)

Using

Sp .99

Numerical

PPV

(using Sp

.99)

SHEEP

TOXOPLASMA

LIVE ANIMAL - Ante

mortem VL 0.00

WHOLE CARCASE

and external surfaces

0.80 VH VL 0.01

LUNGS Parenchyma 0.67 VH VL 0.00

Mediastinal

LNs -- VL 0.00

HEART Myocardium 0.50 VH VL 0.01

SPLEEN

0.67 VH VL 0.01

LIVER Parenchyma 0.67 VH VL 0.01

GI SYSTEM Intestines

0.90 VH VL 0.01

Mesenteric LNs -- VL 0.00

KIDNEYS Parenchyma 0.75 VH VL 0.01

CATTLE

MAP

Live animal M 0.43

Whole carcase

0.75 H VH 0.95

Intestines

0.80 VH VH 0.98

Mesentery

0.50 M VH 0.97

Mesenteric LNs 0.50 M VH 0.96

31

Annex 3 – Sources of data used in the piloting of the model

Databases Reports

MHS MI Data Johne’s in cattle; Animal Health Australia, 2000(Badman, 2000)

MHS/FSA TB Data University of Reading, 2003 (Bennett and Ijpelaar, 2003)

BCMS – Cattle slaughter data VIDA 2008 Report, VLA (VLA, 2008)

DEFRA - Slaughter data: C, S and P EBLEX Pig Yearbook 2009

Literature

(Buergelt et al., 1978) (Corner et al., 1990)

(Gracey et al., 1999) (Radostits, 2000)

(Elbers et al., 2002) (Elbers et al., 2003)

(Brady et al., 2008) (Liebana et al., 2008)

(Seth et al., 2009)

32

Annex 4 – Experts’ profiles

I. MEAT INSPECTION EXPERTS

CODE SPECIES INSPECTI

ON TASK

YEARS

OF

SERVIC

E

ANIMALS

INSPECTED

CURRENT

WORK PLACE

Exp1 C,S AM 8 S – 0.5 million

C – 0.06

million

SE England

3,500 sheep/wk,

300 cattle/wk

Exp2 C,S PM >10 S – 3 million

C – >0.3

million

SE England

3,500 sheep/wk,

300 cattle/wk

Exp3 C,S PM >20 S – 10 million

C – 0.2

million

SE England

3,500 sheep/wk,

300 cattle/wk

Exp4 P AM 6 0.9 million SE England

7,000 pigs/wk

Exp5 P PM 14 4 million SW England

>12,000 pigs/wk

Exp6 P PM 21 3.5 million SE England

7,000 pigs/wk

AM –Ante mortem; PM – Post mortem; C – Cattle; S – Sheep; P – Pigs; SE – Southeast;

SW – Southwest

II. LABORATORY EXPERTS

Dr. Stefanie Schmeiser

Research Assistant

Institute of Virology

Centre for Infectious Diseases

University of Veterinary Medicine Hannover, Foundation

Germany

@ [email protected]

Since 10/2008, Dr. Schmeiser works as research assistant in the EU Reference

Laboratory for CSF.

mailto:[email protected]

33

Dr. Sandra Blome

Head of German national reference laboratory for CSF and ASF

Institute of Diagnostic Virology

Friedrich-Loeffler-Institut

Germany

@ [email protected]

Dr. Blome previously worked in the EU Reference Laboratory for CSF in Hannover.

Dr. Klaus Depner

Deputy head of working group International Animal Health / Head of Laboratory

Institute of Diagnostic Virology

Friedrich-Loeffler-Institut

Germany

@ [email protected]

- Until summer 2010, Dr. Depner worked in the European Commission and was

responsible for notifiable diseases in swine (CSF, ASF, Aujeszky’s disease, SVD). He

has previously worked in the EU Reference Laboratory for CSF in Hannover, and

has published numerous publications on CSF and virology.



34

Annex 5 – Protocol for the extraction of data from expert consultation

I. GENERAL – NO EXTREME* VARIATIONS BETWEEN ESTIMATES

Scenarios: Estimates or values given by

experts

Figure to be used for the model

Expert gives single value estimate Use same value for model

Expert gives an estimate within a range of

50 percentage points (i.e. 2 extremes are

less/equal then 50 percentage points)

Use average of the range given

Expert gives estimate as (equal or) less

then<x

Use x (conservative approach)

Expert gives estimate as (equal or) more

then<x

Use (1-x)/2

Expert gives qualitative range estimate:

very low, low, medium/moderate, high,

very high or similar expressions

Use as figure the average from the Se or PPV

range (see table for the same hazard group) that

corresponds to the estimate/description given

Different experts give values that are not

more than 50 percentage points apart

Use as figure the average of the estimates

Different experts give ranges of values

whose averages are not more than 50

percentage points apart

Use as figure the average of the averages of the

ranges

II. EXTREME* VARIATIONS WITHIN SAME EXPERT


experts


Experts gives two values with a range

bigger than 50 percentage points

- Contact expert and request clarification

- Give expert the opportunity to think again

and wait for eventual revision of the values

- If no revision, use average of the range

III. EXTREME* VARIATIONS BETWEEN EXPERTS


experts


Experts give values that are more than 50

percentage points apart or the averages of

the expert’s estimates are more than 50

percentage points apart

-Contact both experts and request clarification

-Give experts the opportunity to think again

and wait for eventual revision

-If a value is revised and the variation between

the estimates falls below extreme, follow the

steps outlined earlier

35

- if no value is revised and the difference is still

extreme*, check in literature for support for one

of the two opinions.

- If nothing can be found in literature, use own

opinion to produce a final estimate after taking

into account the quality of the reasoning of the

experts, their experience etc.

* Extreme is a variation when the difference between the two estimate values is

more than 50 percentage points



Project MC1003

Assessment of the benefit to public and animal health, and animal welfare of post-mortem inspection of green offal in red meat species at slaughter

and


Project Report N.5: A qualitative risk assessment for specific hazards associated with the current and alternative green offal inspection activities.

Authors: Annette Nigsch, Resident of the European College of Veterinary Public Health (ECVPH)1

Bojan Blagojevic, PhD student and ECVPH resident2

Silvia Alonso, Lecturer in Veterinary Public Health1

Katharina Stärk, Professor in Veterinary Public Health1

Neville Gregory, Professor of Animal Welfare Physiology1

1Department of Veterinary Clinical Sciences, RVC

2 Department of Veterinary Medicine, Faculty of Agriculture,

University of Novi Sad, Serbia

2

Assessment of the benefit to public and animal

health, and animal welfare of post-mortem

inspection of green offal in red meat species at

slaughter


PROJECT REPORT N.5 (Objective 5) – A qualitative risk assessment

for specific hazards associated with the current and alternative green

offal inspection activities.

3

GLOSSARY

AH Animal Health

AM Ante-mortem inspection

AW Animal Welfare

Cfu Colony forming unit

CSF (V) Classical Swine Fever (Virus)

ELISA Enzyme-linked immunosorbent assay

FCI Food chain information

GO Green offal

MAP Mycobacterium avium spp. paratuberculosis

M. bovis Mycobacterium bovis

MI Meat inspection

PH Public Health

PM Post-mortem inspection

QMRA Quantitative Microbiological Risk Assessment

Se (Test-) Sensitivity, ability of a test to detect diseased animals correctly

Sp (Test-) Specificity, ability of a test to detect animals without disease

correctly

TB (bovine) Tuberculosis

T. gondii Toxoplasma gondii

YOPIS Young, old, pregnant, immune-compromised and sick

4

TABLE OF CONTENT

GLOSSARY .......................................................................................................................... 3

AIMS AND OBJECTIVES OF THE STUDY .................................................................... 5

MATERIALS AND METHODS ........................................................................................ 6

1. Research questions ............................................................................................... 6

2. Risk assessment – Codex Alimentarius framework ........................................ 7

3. Model input parameters .................................................................................... 17

BACKGROUND INFORMATION FOR SELECTED HAZARDS .............................. 20

MAIN FINDINGS AND CONCLUSIONS (BY HAZARD) ........................................ 25

Mycobacterium bovis ....................................................................................................... 25

Mycobacterium avium subsp. paratuberculosis ............................................................. 26

Toxoplasma gondii ........................................................................................................... 27

Salmonella ........................................................................................................................ 27

Classical Swine Fever ................................................................................................... 28

Abdominal and inguinal hernia.................................................................................. 29

Tail biting ....................................................................................................................... 30

GENERAL DISCUSSION................................................................................................. 31

Model constraints due to input data quality............................................................. 32

Lack of data in the context of the specific hazards ................................................... 33

CONCLUSIONS ................................................................................................................ 34

Recommendations for further research ..................................................................... 34

ACKNOWLEDGEMENTS ............................................................................................... 36

REFERENCES .................................................................................................................... 37

ANNEX ............................................................................................................................... 41

5

AIMS AND OBJECTIVES OF THE STUDY

This report describes the outcomes of objective 5 “Evaluation of risk for public health,

animal health and animal welfare associated with the current green offal inspection

activities” of project MC1003 and is based on preparatory work accomplished as part

of objective 4 “A generic risk pathway of inspection tasks currently undertaken during

slaughter and at primary production level” of the same project.

The scope of objective 4 was to create a generic risk pathway of meat inspection (MI)

by mapping inspection tasks at slaughterhouse level, during transport and at

primary production level.

In objective 5, this risk pathway is used as the basis for a qualitative assessment of

the risk to public health (PH), animal health (AH) and animal welfare (AW) for a

selection of hazards in the context of the current and alternative green offal (GO)

inspection activities. This aim is achieved via the following tasks:

Development of a risk assessment framework for the MI process;

Development of a qualitative score system of the level of risk to PH, AH and

AW;

Evaluation of risk associated with different “inspection scenarios”;

6

MATERIALS AND METHODS

1. Research questions

The work addressed three questions, reflecting the diverse aspects of hazards and

lesions in slaughtered animals. Every question was separately assessed for seven

hazards.

Scenario 1 – current GO inspection

1) What is the probability of a carcase carrying hazard X or a condition

associated with hazard X (see box 1 for details) at point of chilling under the

current practice of green offal inspection?

Scenario 2 – visual GO inspection

2) How does the probability of a carcase carrying hazard X or a condition

associated with hazard X change if only visual inspection is carried out on

green offal (i.e. gastric and mesenteric lymph nodes are not palpated?

Scenario 3 – absence of GO inspection

3) How does the probability of a carcase carrying hazard X or a condition

associated with hazard X change in the absence of green offal inspection?

The estimates obtained above are then used to make an evaluation of the changes in

risks for PH, AH and AW derived from the different GO inspection scenarios.

Definitions

Green offal is defined in this project as: stomachs, guts, mesentery, and gastric and

mesenteric lymph nodes.

In the context of this project, the terms “probability of carcases carrying a hazard”

and “probability of carcases carrying a condition associated with a hazard” will be

interchangeably used with “hazard prevalence” and “lesion prevalence”

respectively.

7

2. Risk assessment – Codex Alimentarius framework

The generic model for risk assessment is based on Codex Alimentarius Commission

standards [1] with the following components:

(Risk pathway)

Hazard identification

Hazard characterization

Exposure assessment

Risk characterization

Box 1. Presence of hazard versus presence of lesion/condition

Depending on which of the three aspects of risk (PH, AH and AW) is considered, either “presence of

hazard” or “presence of lesion/condition” are the parameters of relevance.

Parameters relevant to Public Health

Food-borne pathogens – if ingested by the consumer – have the potential to cause clinical signs, ranging

from mild to life-threatening conditions in humans. Therefore, presence of hazard constitutes a potential

risk to human health.

Parameters relevant to Animal Health

The animal health findings at the abattoir are valuable in the context of AH surveillance and in particular

for early detection of notifiable diseases. If an infected animal goes to slaughter, the following two detection

levels are to be considered:

o Lesion not detected

A lesion may not be detected and therefore the hazard will still be present in/on the carcase

with a risk of silent spread. The parameter of interest in this case is the probability of a

carcase carrying an undetected lesion at the point of chilling.

o Hazard not confirmed

When a lesion is detected but the specific hazard is not confirmed with appropriate testing

(and the carcase is therefore not rejected), this will result in the delay of the detection of an

outbreak and allow for silent spread. In this case, the parameter of interest is the probability

of a carcase carrying a hazard at the point of chilling.

Parameters relevant to Animal Welfare

As with AH, the information gathered during MI can be communicated to the farm of origin or the

authorities to ultimately result in a better AW status at the production site as well as during transport. The

parameter of most importance is therefore the probability of an animal carrying the lesion at the point of

chilling.

8

2.1. Risk pathway

The risk assessment focuses on the steps that occur at the abattoir, from the point

where animals enter the abattoir (e.g. lairage) to the point where dressed carcases are

health marked and enter the chilling room (fig. 1). The first module in the model

represents the lairage, where FCI is checked and ante-mortem inspection is carried

out. Based on these two controls, a decision is made as to whether animals should go

on to routine slaughter or are considered not fit for slaughter. After this step,

slaughter begins with stunning and follows with the carcase dressing until the stage

of evisceration. In some species (bovines), removal of the head is carried out at this

stage for consequent head inspection. After the evisceration phase, i.e. removal of

red offal and GO, these offal are inspected. Carcase dressing continues after

evisceration until the end of the slaughter line, where the dressed carcase is

inspected and, if approved, sent to the chilling room.

The risk assessment models the inspection tasks that occur along the MI process. For

each hazard, only those inspection practices that are likely to impact on the

lesion/hazard prevalence along the slaughter process are modelled (i.e. heart

inspection is not considered in the risk assessment relative to Mycobacterium bovis, as

the contribution of this MI task to the detection of this hazard is known to be

negligible; information was based on findings from previous parts of the project - see

Report N.1). Furthermore, for some of the hazards, additional steps are considered

whenever relevant (see later chapters for more details). Figure 2 shows a graphic

representation of the risk pathway.

The final estimate in this risk assessment is the proportion of carcases with a hazard (or

condition) at the chiller in a single slaughter day. This output, for each of the three

scenarios simulated, is the basis for the final risk estimation.

9

Figure 1: Representation of slaughter process and relevant main inspection steps.

Inspection practices modelled Scenarios

Lairage

Stunning

Carcase dressing to evisceration

Evisceration

Carcase dressing after evisceration

Carcase at the end of slaughter line

Carcase at the beginning of chilling

FCI checking and ante-mortem

inspection

Head inspection (if applicable)

Red offal inspection

Green offal inspection

1. Traditional GO inspection

2. Visual GO inspection

3. Absence of GO inspection

Output: presence/detection of hazard/lesion within each

of the three scenarios for green offal inspection

Slaughter step

Dressed carcase inspection

10

Figure 2. Outline of risk pathway. (presented inspection steps are only examples). The blue box represents the intermediate model outcomes. The orange box indicates the final model outcome.

Prob. infected animal

showing clinical

signs

Prob. clinical

signs detected

Prob. action

is taken

px = * *

STEPS IN THE RISK PATHWAY

pb

pc

pd

pe

pf

pa

Infected animal at

lungs inspection

Infected animal at

pleura inspection

Infected animal at

peritoneum inspection

Infected animal at whole

carcase inspection

Carcase carrying

hazard/lesion at chilling

Infected animal at

slaughterhouse

Infected animal at

AM inspection

Infected animal at

head inspection

11

2.1.1. GO inspection scenarios modelled

The following three scenarios of GO inspection are modelled for each hazard:

Scenario 1 - “Traditional”:

Inspection of GO as laid down in Regulation (EC) No.854/2004 for cattle and

pigs;

Visual inspection of stomach and intestines, mesentery, gastric and

mesenteric lymph nodes;

Palpation of gastric and mesenteric lymph nodes.

Scenario 2 - “Visual”:

Only visual inspection of stomach and intestines, mesentery, gastric and

mesenteric lymph nodes;

No palpation of lymph nodes;

For small ruminants this scenario is already in place as the current

requirements involve only visual inspection of GO.

Scenario 3 - “Absent”:

Absence of all GO inspection tasks;

Absence of all GO inspection is illegal/non-compliant under the current European

legislation. The risk difference between scenarios 2 and 3, and between scenarios 1

and 3 can be interpreted as an estimate of the proportion of carcases carrying the

hazard which are only detected via GO inspection.

2.2. Hazard identification

A comprehensive list of hazards to PH, AH and AW related to meat production was

identified in objective 1 of project MC1003 (see report N.1). In consultation with the

Food Standards Agency, seven hazards were selected as the focus of this part of the

project. The selection, which followed the steps outlined below, was made so as to

represent a broad range of hazards.

12

Selection process:

Step 1: Hazards that cannot be detected with GO inspection were excluded. The

reason is that no change in risk can be observed for such hazards as a

consequence of changes in GO inspection1.

Step 2: Hazards/conditions that are primarily present in/on very young animals

(calves, young lambs, and piglets) were excluded in order to concentrate on

hazards relevant to the age groups of bovines, small ruminants and swine

most commly slaughtered.

The final selection included the following hazards (in brackets the disease related to

the hazard):

Public Health interest:

Toxoplasma gondii (Toxoplasmosis) in sheep;

Salmonella spp. (Salmonellosis) in pigs;

Animal Health interest:

Mycobacterium bovis (Tuberculosis/TB) in cattle;

Mycobacterium avium subsp. paratuberculosis (MAP) in cattle;

Classical Swine Fever virus (CSF) in pigs;

Animal Welfare interest:

Abdominal and inguinal hernia in pigs;

Tail bite in pigs.

2.3. Hazard characterization

Hazards were characterised according to the following aspects:

Values at risk:

o PH, AH, AW;

Animal species:

o Bovines, small ruminants, pigs;

Detection in a single or in multiple organ system(s):

1 Given its animal welfare significance, and after consultation with the Food Standards Agency, it was

decided to include “tail bite” among the selected hazards despite not being detectable at GO

inspection.

13

o Tail bite [single] vs. all other hazards [multiple];

Endemic and exotic notifiable diseases (i.e. not currently present in the

country):

o TB [endemic] vs. CSF [exotic];

Potential amplification at the slaughterhouse (e.g. multiplication and/or cross-

contamination):

o Salmonella [multiplication/cross-contamination] vs. the other hazards;

Macroscopic visibility/in GO:

o Salmonella, TB, MAP, CSF, Toxoplasmosis, hernia [visible] vs. tail bite

[not visible].

2.4. Exposure assessment

The exposure assessment requires the estimation of the “likelihood of a carcase

carrying a hazard/condition” at every step along the risk pathway. The combination

of these “step-probabilities” produces the final likelihood estimate for a specific

hazard.

Within step probabilities:

For each step in the model a “probability of a carcase carrying a hazard/lesion at that

step in the chain” is estimated according to three parameters (box 2):

o Probability of the organ carrying a lesion

o Probability of detection of that lesion by specific MI tasks

o Probability that a corrective action is taken

The within-step probabilities are dependent, and therefore the three probabilities

above were combined according to the matrix provided in table 6, annex 1 (see for

further explanations).

14

Final probability:

During ante- and post-mortem inspection, a series of inspection tasks is carried out

leading to the classification of carcases or parts of it as fit or unfit.

Every MI task can be interpreted as a “test”. The general concept of MI is that the

results of all single inspection tasks are interpreted in parallel. With parallel

interpretation, animals are considered positive (“lesion is present”) if they are found

positive at one or more of the inspection tasks. In quantitative terms the combined

sensitivity of various meat inspection tasks can be calculated with the following

formula [2]:

SeP = Se1 + Se2 – (Se1 * Se2)

Where:

SeP: final sensitivity under parallel interpretation;

Se1, Se2: sensitivities of test 1 and test 2.

Box 2. How meat inspection can lead to a reduction of a hazard.

MI can only lead to a reduction in hazard prevalence if all of the following three criteria are met:

The infected/contaminated animal or carcase shows a macroscopic lesion1

o Dependent on biology of pathogen and the animal;

The lesion can be detected by a MI task

o Dependent on the task itself, the environment (lighting, speed of slaughter line) and the

person performing the inspection (experience, training);

A corrective action is taken that is effective in lowering the hazard impact

o Dependent on legislation and operation manuals, evidence-based judgement of

consequences, traditions, awareness.

These three criteria each have a probability of being met. The overall ability of a MI task to change hazard

prevalence is the product of all criteria. If one criterion is not fulfilled (probability p is 0), the product of the

three criteria will be 0, i.e. the MI task does not have any effect on the prevalence. To result in a hazard

reduction of at least 50 %, all three criteria have to be fulfilled with a combined probability of at least 50 %.

Example: p(criterion 1) * p(criterion 2) * p(criterion 3) = 50 % * 100 % * 100 % = 50 %

1 In the context of this project, macroscopic lesions are those visible to the naked eye and that could be identified under

appropriate conditions, e.g. by an experienced pathologist in an appropriate environment

15

In qualitative terms, this means that a range of tests with low Se can end up with a

combined moderate or even high Se. In our risk assessment, the within-step

probabilities are combined to obtain a final (overall) “probability of a carcase

carrying a hazard/lesion at chilling”. For this purpose, within-step probabilities are

combined according to the matrix provided in table 7 in Annex 1.

MI tasks can reduce the presence of a hazard in the carcase/organ or have no effect.

Therefore, we have not considered the possibility that a MI task causes greater

contamination of a carcase/organ, except where activities at slaughter can

significantly contribute to the carcase/organ contamination (e.g. Salmonella). In this

case the risk pathway includes those steps in the process (both slaughterhouse

activities and meat inspection tasks) that are likely to increase the level of

contamination of the carcase/organ. In this case, the matrix used to combine

probabilities is provided in table 8, annex 1.

See section 3 below (model input parameters) for further details.

2.5. Risk characterization

Risk characterization implies the combination of probability of a hazard occurrence and

its consequences. In this project the risk assessment covers only a segment of the food

chain (slaughter). The risk model therefore provides an estimation of the probability

of occurrence of a hazard, or a lesion associated with a hazard, at chilling (final point

in our assessment). This qualitative estimate obtained from the model is then

evaluated in the context of its potential consequences.

The risk for PH is directly evaluated on the basis of the probability that the hazard is

present at the chiller, and therefore, it is possible for it to reach the consumer. The

consequences were evaluated under the provision that all steps following chilling

will not modify the presence of the hazard. A full evaluation of the risk at point of

consumption would require the evaluation of the effect that subsequent steps and

risk reduction measures after chilling will have on the presence of the hazard in the

food product.

In terms of risk to animal health and animal welfare, the presence of the

hazard/condition at the chiller is an indicator of the failure to detect/identify the

hazard. The consequences are then assessed on two main aspects: impact on (i)

disease notification and (ii) hazard spread.

16

2.5.1. Description of the qualitative categories of likelihood and

consequences

As described above, risk is characterized by a combination of probability of hazard

and its consequences. The qualitative categories of likelihood and consequences used

to obtain the final measure of risk are described in table 1 and table 2.

The quantitative probability ranges presented in table 1 are proposed by the authors

and aim at providing approximate numerical ranges for the qualitative likelihood

categories. These ranges were used to “translate” quantitative input values derived

from literature, official reports and expert elicitation into qualitative values in a

transparent and replicable manner2. The “interpretation” of the qualitative values

provided in the tables can be used to interpret the model results.

Table 1: Definition of qualitative categories of likelihood with quantitative probability ranges used to convert

numerical input data into qualitative probabilities (adapted from [3]).

Likelihood

category

Interpretation Quantitative

Probability

Negligible May occur only in exceptional circumstances or probability of

event is sufficiently low to be ignored

<0.1 %

Very low Would be very unlikely to occur 0.1 % - < 5 %

Low Could occur at some time 5 % - <25 %

Moderate Might occur or should occur at some time 25 % - <75 %

High Is expected to occur in most circumstances 75 % - 100 %

Table 2: Definition of qualitative categories of consequences (adapted from [3]).

Consequences Interpretation

Insignificant Insignificant impact, little disruption to normal operation*

Minor Minor impact for a few individuals, modifications to normal operations necessary,

but manageable*

Major Major impact for a few or many individuals, systems significantly compromised,

increased monitoring required*

* In relation to animal welfare: “operation” or “system” refers to the animal, i.e. animal welfare is

compromised or not.

In relation to public and animal health: “operation” or “system” refers to the operator, whole agricultural sector or society as a whole.

2 the qualitative output of the models cannot be “re-translated” directly into numerical ranges but

should be interpreted in line with the definitions given in tables 1 and 2

17

2.6. Sensitivity analysis

To evaluate the robustness of the model, the scenarios were re-calculated with

altered input values for those parameters that seemed to have the highest impact on

the final outcome. By changing the input parameters that are related to the quality of

MI or the slaughter process, predictions can be made on how the whole system of

slaughter and inspection would react should improvements be introduced at certain

steps in the slaughter process. As such, the results of the sensitivity analysis can be

used to indicate steps potentially suitable to maintain an equal level of protection if

current MI practices were modified.

Alternative scenarios, the values used in the sensitivity analysis and the outcomes

are described in the specific results and discussion sections (annex 3).

2.7. General assumptions

For a list of general and specific assumptions see annexes 2 and 3.

3. Model input parameters

The likelihood of occurrence of desired (hazard reduction) and undesired (hazard

increase) events in the risk pathway depends on multiple risk factors which can be

related to MI or not.

3.1. Factors related to MI influencing the prevalence of a hazard

Three input parameters are needed: probability of presence of lesion in a body part

or organ, probability of detection of this lesion and action taken (see project report

N.3, risk pathway, for details). For post-mortem inspection information on these three

parameters was collected for every single organ (system) to be inspected, such as

whole carcase, head, lungs, gastro-intestinal tract, etc. (tab. 3). For a detailed list of

the body parts and organs to be inspected and the specific MI task see annex 3.

18

Table 3: Factors influencing presence of a hazard in/on a carcase by inspection tasks carried out by official

veterinarians (FCI = check of food chain information, AM = ante-mortem, PM = post-mortem, Lab = laboratory

testing).

Inspection

task

Factor

FCI

Probability that presence of hazard is stated in FCI

Probability that hazard will be detected with FCI check

Corrective action: Probability that animal will be separated (and not be subject to

routine slaughter)

AM

Probability that clinical signs are present

Probability that clinical signs will be detected during inspection

Corrective action: Probability that animal will be separated (and not be subject to

routine slaughter)

PM

Probability that a macroscopic lesion is present in this body part or organ (-system)*

Probability that lesion will be detected*

Corrective action: Probability that whole carcase will be condemned*

* These three factors are repeatedly entered in the model for every body part or organ (-system).

3.2. Factors not related to MI influencing the prevalence of a hazard

Table 4 provides an overview of factors other than MI tasks that are required to

estimate change in hazard/lesion prevalence at the slaughterhouse level.

Table 4: Factors influencing the presence of a hazard in/on a carcase in lairage, during the slaughter process

and additional factors.

Factors influencing the presence of a hazard in/on a carcase in lairage/during ante-mortem

inspection

Prevalence Prevalence of hazard at arrival in lairage

Cross-

contamination

Probability that cross-contamination occurs

If cross-contamination/infection occurs, how many additional animals (what

proportion) will be contaminated/infected

Factors influencing the presence of a hazard in/on a carcase by the slaughter process

Slaughter

process*

Probability that a step in the slaughter process changes the prevalence of a

hazard/lesion*

If a step in the slaughter process can change the prevalence of a hazard/lesion,

what proportion of carcases will carry hazard/lesion after this slaughter step*

Other factors

Chilling Change in prevalence of hazard/ lesion in/on a carcase through chilling

* The slaughter process includes all steps from stunning to trimming of contamination before presentation for

post-mortem inspection. For every step these factors have been collected separately.

19

3.3. Data collection

Data to parameterise the models was collected from peer-reviewed literature, official

reports and data from national and international organizations. Specific findings

presented in report N. 4 of this project were also used to parameterise the models

whenever relevant. Missing input parameters were collected through elicitation of

expert opinion. National and international experts were recruited for this purpose.

The expert elicitation protocol is explained in detail in project report N.4.

20

BACKGROUND INFORMATION FOR SELECTED HAZARDS

Mycobacterium bovis (as an Animal Health Risk)

TB due to Mycobacterium bovis (M. bovis) is a contagious, usually chronic disease of

cattle, characterized by nodular lesions – granulomas with necrosis, caseation and

calcification in lungs, lymph nodes or other organs, including lymph nodes of the

intestines. The bacterium is transmitted among cattle mainly via aerosols; faeco-oral

transmission is important prior to weaning. Preclinical stages of bovine TB can be

detected in live animals by the use of tests of cellular immunity, i.e. the skin, gamma-

interferon and lymphocyte transformation tests [4]. Current MI procedures at the

slaughterhouse were introduced to detect and control TB [5].

Mycobacterium avium subsp. paratuberculosis (as an Animal Health Risk)

Paratuberculosis is a chronic wasting disease of cattle associated with their immune

response to MAP infection. The disease can lead to considerable reduction of

productivity of cattle [6]. A major problem in the control of this disease is the lack of

a reliable diagnostic method to identify animals with subclinical disease [7]. The

disease spreads in cattle by ingestion of M. paratuberculosis from the contaminated

environment and can persist in a herd after the introduction of infected animals.

Infection can spread vertically in-utero or via infected semen. The primary source of

infection in calves is milk from infected cows or milk that is contaminated with the

faeces of shedders.

MAP can be detected in GO in the form of thickened and corrugated intestinal

mucosa and enlarged caecal and mesenteric lymph nodes, often with haemorrhages.

Also, the carcase can present with associated oedema and emaciation. Early lesions

occur in the walls of the small intestine and the draining mesenteric lymph nodes,

and infection is confined to these sites at this stage. As the disease progresses, gross

lesions occur in the ileum, jejunum, terminal small intestine, caecum and colon, and

in the mesenteric lymph nodes. MAP is present in the lesions and, in the terminal

stages, throughout the body [8].

Toxoplasma gondii (as a Public Health risk)

Toxoplasmosis is a common, world-wide zoonosis of increasing concern which is

responsible for major economic losses in livestock, and especially in sheep, through

abortions, still birth and neonatal losses [9]. Other symptoms in sheep include fever,

21

generalized tremor and difficult breathing [10]. On post-mortem, the disease can

present with multiple granulomatous lesions in lungs, necrosis in the liver, spleen

and kidneys, ascites, hydrothorax and intestinal ulceration [10]. Toxoplasmosis is

caused by the protozoan parasite Toxoplasma gondii (T. gondii). The definitive hosts of

the parasite are the domestic cat and other felines; humans, as an intermediate host,

can be infected either through the consumption of undercooked meat contaminated

with cysts of this protozoa (bradyzoites) or by the ingestion of oocysts (shed by

infected cats) in contaminated food and water.

Although it is assumed that roughly 500 million people have been infected with

T. gondii at some point in their life [11], infection with T. gondii is normally chronic

but largely asymptomatic in humans. In about 15 % of cases a febrile illness with

lymphadenopathy is present [12]. However, it may cause stillbirth, blindness, mental

retardation and occasional death of congenitally infected infants [13]. More severe

and complicated disease may occur in immune-compromised patients, including

those infected with the human immunodeficiency virus and those receiving

immuno-suppressive chemotherapy following neoplastic disease or organ

transplantation [14].

Salmonella (as a Public Health risk)

Salmonellosis is a risk to PH through contaminated food and the environment [15].

In 2009 in the UK there were 10,071 laboratory confirmed human cases of

salmonellosis [16]. However, considering the known under-reporting, the total

number of cases in 2009 could be as high as 40,000 [17].

Salmonella Enteritidis and S. Typhimurium account for 60–80% of all human

Salmonellosis. S. Typhimurium is isolated from all domestic livestock. Over the past

five years this serovar was the most commonly found serovar in pigs and accounted

for approximately 70 % of all food related incidents [18]. Yet, the magnitude of the

contribution of pork consumption to human disease with S. Typhimurium is

difficult to quantify [19].

The observed prevalence of slaughter pigs infected with Salmonella spp. in the UK

was 21.2 % (17.8 % - 25 %) [20]. Infection with Salmonella is very rarely associated

with clinical disease in pigs [21]. Only young pigs up to four months are likely to

develop severe clinical signs such as septicaemia, high fever and death [21]. Infected

pigs may become carriers and excrete Salmonella in their faeces intermittently.

Carriers of S. Typhimurium may develop septicaemia or enteritis if their resistance is

22

lowered by environmental stresses (e.g. as pigs are loaded and transported to the

abattoir) or due to concurrent infections [20, 21]. The colon is usually the primary

organ showing lesions related to S. Typhimurium infection, presenting either focal

or diffuse necrotizing colitis [21]. These lesions are potentially detectable by

inspection of the GO. Presence of Salmonella infection does not necessarily result in

carcase contamination, unless faecal spillage occurs from the anus or a damaged gut.

Poor hygiene in a slaughterhouse may result in cross-contamination between clean

and contaminated carcases.

Classical Swine Fever (as an Animal Health Risk)

CSF is a serious and contagious viral disease of pigs and wild boar with a

widespread worldwide distribution. CSF was eradicated from Great Britain in 1966.

Since then outbreaks occurred in 1971 and 1986. A more serious epidemic in East

Anglia in 2000 affected 16 farms [22-24]. An outbreak of this notifiable disease can

cause serious economic losses as a result of export limitations and mass destruction.

Infected herds cannot be treated but must be culled.

Clinical symptoms that can frequently be seen are high fever, gastro-intestinal and

respiratory signs, dullness/apathy, widespread petechiae and ecchymoses,

neurological symptoms, hunched-up back and huddling [25]. The CSF virus together

with secondary bacterial infections, can cause lesions in multiple organ systems,

including haemorrhagic and enlarged lymph nodes, ascites, petechial haemorrhages,

hyperaemic intestinal tract, oedema of mesocolon among others [26]. Clinical

diagnosis continues to pose problems for veterinary practitioners as moderate

strains often cause only subclinical or mild symptoms [27, 28]. Furthermore, an

extensive list of differential diagnosis exists (African Swine Fever, Aujeszky’s

disease, porcine reproductive and respiratory syndrome, porcine dermatitis and

nephropathy syndrome, all forms of bacterial septicaemia and pathogens causing

haemorrhages, intoxication, etc.) [25].

To date, no active surveillance programme is in place in the UK for CSF (Animal

Health, pers. comm.). Detection of a positive animal at the slaughterhouse would

have severe effects on further slaughter processes [29].

23

Abdominal and inguinal hernia (as an Animal welfare risk)

Abdominal (umbilical) and inguinal (scrotal) hernias are relatively common genetic

defects in pigs [30, 31] . The prevalence of hernia varies between 0.4 % to 6.7 %,

depending on breed and environment [30-33].

Direct contact of herniated intestines with skin can cause partial bowel obstruction

with subsequent poor growth performance [30, 31, 34]. Hernias can expand to melon

size; larger hernias usually result in complications; loops of bowel tend to rupture or

leak, resulting in peritonitis, etc. [31]. This results in the production of thick scar

tissue and adhesions between abdominal organs, hindering the evisceration process.

It was reported that over 50 % of pigs with large hernias will be condemned for

peritonitis [31]. Besides the economical loss due to rejected carcases, the extra labour

required during the slaughter process needs to be considered [31, 34]. Larger hernias

are considered a welfare issue, due to the tendency of the hernia sac to get infected,

injured and/or abscessed. Mortality rates are reported to be higher and growth rates

slower in finisher pigs with abdominal or inguinal hernia, compared to unaffected

pigs [34].

Genetic traits are described to have an effect on the musculature of the navel and

may therefore impact on hernia predisposition. However, proper hygiene and

management of piglets (e.g. correct placing of navel clips at farrowing) is suggested

to be more likely to reduce the incidence of umbilical hernias than special breeding

selection [31, 34].

Tail biting (as an Animal Welfare Risk)

Tail biting is an important welfare issue and can considerably compromise the well-

being of pigs. Tail biting has been linked to a range of pathological effects, from

injury of the tail to pyaemia and abscesses in different parts of the body. Such effects

may be associated with a reduced growth rate or, in more severe cases, total carcase

condemnation. Even mild tail damage, restricted to puncture wounds, can cause

pyaemia [35]. Tail biting is described as being the most common cause of secondary

bacterial spread in pigs and subsequently increases the risk of carcases being rejected

due to abscessation [36]. Estimates of tail bite lesion prevalence in the UK vary from

0.19 % to 6.9 % [37-39].

24

There is no reference to the presence of abscesses in GO as a result of tail biting in

the literature. Besides abscessation in the tail and the spine, infection may reach the

lungs. Rarely, other organs such as kidney, heart, liver, umbilicus, head and

peritoneum are affected [36, 39]. Various factors can predispose to tail biting, e.g.

hunger, lack of facilities such as bedding, early weaning, high stock densities,

insufficient trough space, high temperatures, insufficient ventilation, very bright

light, and observing other pigs tail biting [39].

25

MAIN FINDINGS AND CONCLUSIONS (BY HAZARD)

Main results are presented for each hazard in annex 3, together with the results of

the sensitivity analysis and a discussion of the findings. The main conclusions are

summarised in this section. A general discussion of the results follows in a separate

section (general discussion). Table 5 presents a summary of the main results by

hazard.

Table 5: Summary of the qualitative estimates for the three green offal inspection scenarios produced with the risk model: what proportion of carcases with lesions in their green offal will be detected at green offal inspection: AH = Animal Health, AW = Animal Welfare, PH = Public Health, GO = green offal, M. bovis = Mycobacterium bovis, MAP = Mycobacterium avium subsp. paratuberculosis, T. gondii = Toxoplasma gondii, CSF = Classical Swine Fever in a situation with a “single pig” or a “group” of infected pigs in lairage.

Proportion detected

Hazard Risk aspect Traditional GO

inspection

(scenario 1)

Visual GO inspection

(scenario 2)

Absence of GO

inspection

(scenario 3)

M. bovis AH Very low Negligible Negligible

MAP AH Low Low Negligible

T. gondii PH Negligible -* Negligible

Salmonella PH Low Low Negligible

CSF (single pig) AH Low Low Negligible

CSF (group) AH Moderate Moderate Negligible

Hernia AW High High Negligible

Tail bite AW Negligible Negligible Negligible

* T. gondii was assessed for sheep. In small ruminants visual inspection is already in place, i.e. traditional GO inspection = visual inspection.

Mycobacterium bovis

The consequences of M. bovis not being detected during meat inspection at the

slaughterhouse, from an animal health perspective, are of two main types: (i)

presence of the hazard at chiller may allow for potential silent spread of the

pathogen and (ii) lack of reporting to authorities and farmers with its consequences

for disease monitoring and control in the country.

The risk assessment for the current MI system predicts a negligible proportion of TB-

positive carcases to be undetected and present at chilling. This translates into high

protection of animal health, by preventing silent spread of the pathogen and

26

providing the opportunity to detect and report findings to farmers and authorities

the appropriate measures to be taken. The risk does not change significantly when

GO inspection is limited to visual inspection or even when GO inspection is not

conducted, although the model highlights that current GO inspection is in a better

position to detect TB associated lesions in GOs compared to visual inspection only.

This finding can be explained by the fact that TB lesions are more common in other

organs such as lymph nodes and easier to detect by inspection of the head or lungs.

These MI activities greatest contribution is in the protection of AH from the risk of

M. bovis spread.

In conclusion, variations in GO inspection as modelled in this project do not have

any implications for Animal health risk associated with M. bovis.

Mycobacterium avium subsp. paratuberculosis

Visual inspection of GO was found to be an important step in MI for identification of

MAP positive carcases, demonstrating the same effectiveness as the current GO

inspection system that requires palpation and incision in addition to visual

inspection. Both systems will allow for identification and consequent reporting of

disease. Visual inspection is therefore a valuable contributor in identifying MAP at

the slaughterhouse. It follows from this finding that not performing GO inspection

(scenario 3) could result in a great increase in animal health risk derived from this

hazard (i.e. not detection/reporting and potential for silent spread). Nevertheless,

our model predicts a very low probability of carcases carrying the hazard at the

chiller even when GO inspection is not performed. The consequent possibility of

silent spread of the pathogen to the livestock population is therefore limited with

any of the GO inspection scenarios modelled. This is in part due to the very low

prevalence assumed in the model, however, the sensitivity analysis revealed that the

model outputs are not greatly influenced by the disease prevalence. Moreover,

whole carcase inspection was effective at detecting MAP. It is sensible to deduce that

this step will help minimise the number of animals undetected at inspection and

therefore contribute to the protection of animal health if GO inspection is removed.

In conclusion, modification or even elimination of GO inspection would not

necessarily result in an increased AH risk provided that other steps of the meat

inspection process (mainly whole carcase inspection and ante-mortem) are

accurately performed. This is particularly important as monitoring at the farm level

is not conducted.

27

Toxoplasma gondii

The current GO inspection procedure (visual inspection) does not seem to have a

great effect in reducing the PH risk associated with Toxoplasma gondii. In general,

meat inspection at the slaughterhouse is not very efficient in detecting toxoplasma

positive animals. Our model predicts a moderate probability of having infected

carcases at the chiller, with its consequent risk for public health. This is even more

notable considering the relatively high prevalence of the disease in small ruminants

in this country.

The results of the sensitivity analysis, using a lower initial value of T. gondii

prevalence in sheep did not affect the ability of GO inspection to detect the hazard

but decreased the proportion of undected carcases contaminated with the hazard in

the chiller. This suggests that control measures at the farm to reduce prevalence in

the sheep flock may be important when reducing the risk for public health.

The consequences of toxoplasmosis infection in humans are of particular relevance

to certain high-risk groups (mainly pregnant women and immune-compromised

individuals). Given the moderate likelihood of the hazard being present in meat after

inspection and the serious consequences, our risk estimation (considering both

likelihood and consequence) cannot be lower than moderate. Nevertheless, the steps

that follow the slaughter process, and particularly cooking and consumption

patterns, are crucial in protecting consumers from the very serious consequences of

this hazard. Efforts to reduce the PH risk from T. gondii in further steps along the

food chain should aim at the destruction of the cysts through cooking or other ways

of processing. These strategies have proven, to date, to be able to reduce the risk to

an important degree. Another successful strategy to reduce the risk to public health

would be the reduction of disease prevalence in the sheep flock. In addition,

categorization of farms according to disease status could be used as a mechanism to

decide whether meat is to be sold as fresh or used for the production of meat derived

products [40].

Salmonella

The slaughter process is a crucial step in the spread of Salmonella and the resulting

PH impact. The slaughter activities determine significantly the degree to which

carcases will be contaminated at the end of the line. The MI process, as such,

contributes to a much more limited degree (very few MI tasks will detect the visual

28

conditions associated with Salmonella). This is the case for GO inspection, given that

the most characteristic condition associated with Salmonella is enteritis.

GO inspection can only lead to an effective change of prevalence of Salmonella in

carcases at chilling if a) a visible condition is present on the carcase/organ which is b)

detected and c) a corrective action is taken. In the case of Salmonella the probabilities

of a carcase/organ showing a lesion and being condemned are both very low. As a

result, there are not major differences among the three GO inspection practices, even

if the traditional GO inspection (scenario 1) has a high detection rate and without GO

inspection (scenario 3) the detection rate is negligible (see fig. 2). In summary, missing

a low number of lesions in the gastrointestinal tract as a consequence of not

performing GO inspection or performing only visual inspection does not influence

the overall probability of having Salmonella-positive carcases at the point of chilling.

Therefore, a change of GO inspection does not seem to modify the risk for PH

associated with this pathogen.

Salmonella is one of the most prevalent foodborne pathogens in the UK and an

important Public Health hazard. It affects a large number of individuals every year

causing serious threat to some patients. The economic consequences derived from

the high number of cases are also of significance. It is accepted that the slaughter

process is a crucial step in controlling the contamination of meat. However, control

strategies applied in the remaining steps of the food chain can contribute

significantly to reducing the risk to public health posed by this pathogen.

Classical Swine Fever

The results of our risk model indicate that infected animals can be to great extent

detected with ante- and post-mortem inspection. The contribution of GO to the

detection of CSF is great, as lesions are usually present in those organs. Nevertheless,

the impact of GO inspection on the probability of having CSF positive carcases in the

chiller does not change for the different scenarios, as the probability of CSF positive

carcases (or a carcase with CSF related lesions) immediately before GO inspection

was already very low in all three GO scenarios. As a consequence the final proportion

of CSF-positive carcases in the chiller does not change substantially, whether or not

GO is inspected. This may be due to the fact that most infected animals with lesions

show pathology in various organs other than GO and therefore are likely to be

detected with other MI tasks early on in the inspection process. So GO, although

29

being effective in the identification of the hazard, has only a limited impact in

protecting AH in relation to CSF.

As described in previous chapters, two different types of risk have to be

differentiated in the context of AH. First, if a CSF-positive carcase does not lead to

disease suspicion and consequent reporting, no disease control measures will be

started and CSF can silently spread to more farms before being detected. It is clear

from our results that the Se of the MI as a “diagnostic system” is dependent on the

number of pigs that show lesions, as can be seen by the difference in detection

between a single pig and a group of infected pigs. The more pigs with clinical signs

or pathological abnormalities, the greater the anticipated capacity of the MI system

to detect CSF. The question remains if, after a carcase is rejected, samples will be

submitted for further laboratory investigation to confirm or rule out CSF. Between

2008 and 2010 less than five CSF suspicions per year were raised in UK abattoirs

(Animal Health, pers. comm.). Another risk to AH exist if only macroscopic lesions

are trimmed from a carcase or its organs and the rest of the carcase enters the food

chain. Even if EU legislation forbids feeding of swill, illegal activities or lack of

awareness pose a residual risk to the pig population of this country.

In both situations above – missing lesions or missing infected carcases - the

consequences are severe, as an outbreak of CSF will not only have serious

implications for infected premises and pig production units in the surrounding area,

but for the whole UK pig industry.

Abdominal and inguinal hernia

The contribution of MI tasks to the identification of hernias is high. GO inspection

shows a good capacity to detect hernias, as do many other MI steps such as

antemortem and peritoneum inspection. This demonstrates that MI is a valuable tool

in the identification of this AW concern.

In general, the prevalence of abdominal and umbilical hernias was assumed to be

very low. As lesions associated with hernia will be detected with a high probability

during visual inspection of the whole carcase and the peritoneum, the contribution

of GO inspection, irrespective of scenario and detection probability, does not change

the final negligible prevalence of having lesions in the carcase at point of chilling.

Protection of AW requires both the identification and subsequent reporting of the

finding. The literature and other consulted sources, stated that there are reasons to

30

believe that gross pathologies associated with hernia are sometimes not identified as

hernias (consulted experts, personal communication). In this situation, the impact of

MI on the protection of AW is questionable, despite MI providing a very suitable

system for hernia identification.

We found that changes in the GO inspection system will not result in a different

probability of detecting hernias. This is due to the fact that, although GO inspection

provides an opportunity to identify hernias, other steps exist in the inspection

system where hernias are detected. As a consequence, reducing GO inspection to

visual or even not performing it will not have a major effect on AW.

Tail biting

GO inspection has very limited contribution to the detection of tail biting in pigs.

Modification to this inspection step will not influence the AW risk.

Inspection at the slaughtherhouse as a whole is of value to the identification of this

condition. Nevertheless, as with other AW concerns, the point of interest is whether

findings are then reported. This is the mechanism that ultimately impacts on AW.

It could be concluded that, the probability of detecting tail biting during inspection

at the slaughterhouse is high, but it is also relatively unlikely that lesions associated

with this AW concern will be misdiagnosed, reducing the final probability that the

problem is reported and action taken. The impact of this is even bigger if those

missed (or not reported) cases show a severe form, e.g. partial or total loss of the tail

or abscessation [54], conditions that can significantly compromise the well-being of

pigs.

31

GENERAL DISCUSSION

The application of risk models at abattoir level creates the opportunity to compare

the outcome of different scenarios. By changing single input parameters the most

influential steps in the risk pathway contributing to the outcome can be identified.

But in recent risk assessments MI was not considered as a hazard reduction step [55],

and it is often neglected [46], or even treated as another source of cross-

contamination [47]. The model described here may compliment other risk

assessments of hazards related to meat production so that risk estimation at abattoir

level can be undertaken in a consistent and transparent manner.

The risk assessment for the three different inspection scenarios for ruminants

showed that the current GO inspection regime is of very limited significance for

bovine TB, MAP and toxoplasmosis. Results indicate that removal of this specific MI

task would not make a substantial difference in the detection of these hazards and

the subsequent risk to AH and PH, respectively. Similarly, for hazards in pigs

(Salmonella, CSF, hernia, tail bites) the model indicated no change in the probability

of a carcase carrying a hazard or lesion if the GO inspection is performed in any of

the alternative GO scenarios. The relative contribution of GO inspection was also

found to be limited because lesions manifested in GO alone are rare and therefore

there would be a high probability of detecting lesions indicative of hazards by other

MI tasks.

The importance of abattoirs as points of (early) detection of AH related conditions is

widely accepted. MI offers the unique possibility to link pathological findings to

conditions recorded during ante-mortem. However, the extent to which the

slaughterhouse allows for efficient monitoring is not the same for all animal

diseases. Our results suggest no difference in risk for CSF, MAP and T. gondii

regardless of whether certain MI tasks are carried out or not.

A third important purpose of MI is the identification of welfare issues in live/dead

animals and carcases, which appear to have been caused on the farm of origin or

during transport (Manual for Official Controls, Food Standards Agency). A range of

conditions that compromise the animal’s welfare can be detected in the lairage and

lesions can be seen during the inspection of carcase and offal. The examples included

in this report are hernia and tail bites in pigs for all of which GO inspection did not

seemed to be a critical detection point.

32

The model was applied to two PH hazards (Salmonella spp. and T. gondii). In terms of

PH, the consequences of hazards not detected at meat inspection can only be

estimated incompletely as intermediate steps between slaughterhouse and consumer

have not been analyzed in this project. Attempting to make conclusions about the

PH risk associated with these hazards by looking at the results of our model will be

incorrect and produce misleading conclusions. Therefore in the discussion of our

individual results the PH risk is indicated assuming that the prevalence of the

hazard does not change along the remaining food processing/consumption steps.

Our results further highlighted the inter-dependency of the presence of a lesion, its

detection and the corrective action triggered by this finding. Even the most effective

MI task (detecting all macroscopic lesions) will not lead to a successful reduction if a

hazard rarely produces lesions or if no action is taken after lesions are detected. In

the context of AH and AW, the value of detection depends largely on the quality and

completeness of the communication of findings during meat inspection and the

degree of follow-up and the corrective actions taken.

Model constraints due to input data quality

Due to a lack of information, several simplifying assumptions had to be made in

order to develop this model. To address this, a sensitivity analysis was undertaken

whenever background information for an input value was not available at all or

different data sources did not provide consistent estimates. By changing the input

parameters that are related to the quality of MI or the slaughter process, predictions

can be made on the overall effect of the whole system of slaughter and inspection

when improvements are made at certain steps in the slaughter process. As such, the

results of the sensitivity analysis identify steps that could be altered in order to

maintain the current level of protection inspite of other changes to MI practices.

If in the future this risk model were to be used for hazards of less public and

scientific interest (e.g. as compared to M. bovis or Salmonella) even more input

parameters may have to be based on expert opinion as oppposed to imperical data.

33

Lack of data in the context of the specific hazards

M. bovis: For most hazards, the literature tends to report the overall proportion of

animals found with lesions. No further distinction is made if these lesions were

solely found in one or in several body parts or organs and whether the hazard was

already suspected during ante-mortem inspection.

MAP and T. gondii: An important data gap in relation to these two hazards was the

lack of information on how many carcases are truly MAP or T. gondii-positive, as

laboratory testing is not performed routinely if lesions are detected at the

slaughterhouse.

Salmonella: Uncertainty remains on whether a relationship exists between the extent

of cross-contaminated and the prevalence of Salmonella shedding animals.

Furthermore, the suggested reported impact of different slaughter processes on the

prevalence of Salmonella as measured by carcase swabs varies. A third difficulty is

the between-batch variation in Salmonella prevalence at point of arrival at the lairage.

CSF has not been present in the UK for more than ten years. Therefore, estimates of

the probability that lesions would be detected are highly uncertain. The low number

of submissions to rule out CSF in the last three years (Animal health, pers. comm.)

indicates that CSF is suspected very rarely in slaughterhouses and disease awareness

is low.

Tail bites and hernia: For these AW-related hazards, the figures for prevalence

presented in scientific studies, reports and expert elicitation were in general

considerably higher compared to the figures obtained from records of rejection data

provided by the Food Standards Agency. This introduces uncertainty in the

quantification of the risk by the model.

34

CONCLUSIONS

The most important limitations of the current MI system are related to its

inability to detect hazards that are not detectable by sensory means (i.e.

visible inpection, palpable) as hazards either:

o do not produce lesions (or not in slaughter-age animals) or

o the lesions are present below the visible or palpable detection limit of

the meat inspector.

In the context of the seven hazards evaluated (Mycobacterium tuberculosis,

Mycobacterium avium subsp paratuberculosis, Toxoplasma gondii, Salmonella spp.,

classical swine fever, abdominal and inguinal hernia and tail biting), the

current GO inspection regime contributes to a limited degree to the detection

of these hazards and the subsequent reduction in risk to PH, AH and AW.

Even though the contribution of GO inspection to reducing the amount of

carcases carrying hazards/lesions at chilling seems to be limited, GO

inspection can provide valuable information with regard to AH and AW

related hazards.

In order to obtain a more accurate estimate of the PH risk associated with

specific hazards, further steps of the food chain should be included in the risk

pathway and modelled accordingly.

Recommendations for further research

In this project a qualitative risk assessment has been developed and applied to a

number of hazards. Qualitative estimates do not represent standard measurements,

but give a relative appreciation of an input/outcome value. To obtain a more specific

estimate of risk it would be valuable to undertake a quantitative risk assessment.

This would also contribute to the validation of the findings presented in this report.

However, robust, accurate and sufficiently detailed data needed for such models are

often not available. Resources should be allocated to improve the quality and

amount of available data.

35

Observation studies could be undertaken to assess quantitatively the degree to

which specific slaughter processes increase or decrease the probability of a carcase

carrying a hazard. These findings will be especially important for hazards that can

be amplified at the slaughterhouse, e.g. cross-contamination with Salmonella.

It would be valuable to obtain more precise estimates of the current detection rates

of various lesion/conditions at the slaughterhouse by the different MI tasks, both at

ante-mortem and post-mortem inspection. Routine monitoring of these findings is

available, however, the quality of the recording often limits the use of these data.

Rejection records should be made more specific and include information on the type

of lesion/condition detected and possibly on the MI task that facilitated its detection.

Experimental studies could also be conducted to obtain this type of information.

Experimental studies aimed at evaluating the effect of modifiying the current GO

inspection procedures should be undertaken to confirm the findings of this project.

Finally, for a more holistic and comprehensive risk evaluation, a full “farm to fork”

assessment is needed. This would allow obtaining a more accurate measure of risk

accounting for the impact that other practices along the food production chain have

on the prevalence of hazards and their consequences for PH, AH and AW. The risk

model developed as part of this project could be expanded for this purpose.

36

ACKNOWLEDGEMENTS

The authors wish to thank the Food Standards Agency for commissioning this

research.

Sincere thanks go to the Department for Environment, Food and Rural Affairs,

Animal Health and the Veterinary Laboratories Agency for provision of data and

reference.

We are very grateful to all experts who have assisted in the study, particularly to Lis

Alban and Lueppo Ellerbroek for guidance and support.

Finally, we are especially grateful to Nikolaos Dadios for all preparatory work and

advice throughout this project.

37

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European Legislation

Regulation (EC) No 854/2004 of the European Parliament and of the Council of 29

April 2004 laying down specific rules for the organisation of official controls

on products of animal origin intended for human consumption.

41

ANNEX

Annex 1

Combination of qualitative risk categories along the risk pathway

Annex 2

General model assumptions

Annex 3

Results and discussion by hazard

Annex 4

Model assumptions, input data, data sources and data gaps

Annex 5

Meat inspection tasks according to Regulation (EC) No 854/2004

42

Annex 1 - Combination of qualitative risk categories along the risk pathway

Models attempt to describe the real situation in a simplified way by identifying and

characterizing generic rules for the way events are interlinked. Such events can be

either dependent on (conditional) or non-dependent from each other.

Example for dependent events: a lesion can only be detected with a MI task if the

lesion is present in the respective organ.

Example for independent events: cross-contamination of pig carcases with Salmonella

may happen during the dehairing process whether or not the prevalence of bacteria

on the carcase surface was reduced by scalding.

In this model the following two rules apply:

Within a step probabilities are dependent;

Between steps probabilities are non-dependent.

A graphic representation of the model is given in figure 2.

Combination of qualitative risk categories of dependent steps

Within every step a number of probabilities are to be combined. Table 14 provides

the matrix applied to combine likelihood categories of dependent steps.

Example: The probability of a carcase being rejected depends on three probabilities:

Probability that a lesion is present in an organ (e.g. moderate);

Probability that this lesion will be detected with the specific MI task

(e.g. high);

Probability that a corrective action is taken (e.g. very low).

The combined probability of rejection will be:

(moderate * high = moderate) * very low = very low

43

Table 6: Combination matrix used to evaluate the likelihood if the subsequent event 2 depends on the

previous event 1.

Event 1

Event 2

Negligible Very low Low Moderate High

Negligible Negligible Negligible Negligible Negligible Negligible

Very low Negligible Negligible Very low Very low Very low

Low Negligible Very low Very low Low Low

Moderate Negligible Very low Low Low Moderate

High Negligible Very low Low Moderate High

Combination of qualitative risk categories of non-dependent steps

The main steps of the risk pathway (as laid out in figure 1) are understood to have

an effect on the prevalence of hazard/lesion which is not dependent on the previous

or subsequent steps.

Table 14 and table 15 provide the matrix applied to combine likelihood categories of

non-dependent steps. These steps can affect the probability in two possible

directions:

Reduce the prevalence of the hazard/lesion

Increase the prevalence of the hazard/lesion

If a step is successful in reducing the prevalence this “change(-)” will be

“subtracted” from the prevalence prior to the step (tab. 14). If a step increases the

prevalence this “change(+)” will be “added” to the prevalence correspondingly (tab.

15).

Example: Assumed that the surface prevalence of Salmonella in pigs was moderate

before scalding and scalding is able to reduce the prevalence to a high degree, then

the combination of prevalence and change(-) is: moderate – high = low

44

Table 7: Change(-): combination matrix of non-dependent events used to evaluate the likelihood when the

subsequent event (2) leads to a decrease in prevalence of the hazard/lesion in relation to the previous event

(1).

Event 1

Event 2


Negligible Negligible Very low Low Moderate High

Very low Negligible Very low Low Moderate High

Low Negligible Very low Low Moderate High

Moderate Negligible Negligible Very low Low Moderate

High Negligible Negligible Very low Low Moderate

Table 8: Change(+): combination matrix of non-dependent events used to evaluate the likelihood when the

subsequent event (2) leads to an increase of prevalence of hazard/lesion in relation to the previous event (1).

Event 1

Event 2


Negligible Negligible Very low Low Moderate High

Very low Negligible Very low Low Moderate High

Low Negligible Very low Low Moderate High

Moderate Very low Low Moderate High High

High Very low Low Moderate High High

45

Annex 2. General model assumptions

It is assumed that all criteria, as laid out in relevant legislation, are

accomplished by the slaughterhouse operator and staff;

Slaughter takes place in slaughterhouses with automated processes and with

a single slaughter line (risk related to manual slaughter are not considered);

All animals are of typical slaughter age and show, for each hazard, lesions

typical for animals of this age. Typical slaughter ages for the UK are:

o Cattle: 18 months to 4 years (67 % of cattle) [56, 57];

o Sheep: 6 months to 1.5 years (84 % of sheep) [58];

o Pigs: 5 - 6 months (>80 % of pigs) [59].

The risk pathway focuses on animals (and carcases) which are subjected to

routine slaughter. Animals that are separated at the stage of FCI check or ante-

mortem inspection or animals that have to undergo emergency slaughter are

not included as we assume that a range of additional and more targeted

inspection tasks are applied to these animals. This handling and attention is

deemed not to be representative for the majority of animals inspected at

slaughter;

Only obligatory MI tasks are included in this pathway (as listed in annex 3).

Cross-contamination in the slaughter hall (e.g. due to splashing, physical

contact between two carcases, insufficient cleaning and disinfection of the

slaughter hall after the end of the slaughter process) is not a stand-alone step

in the risk pathway, but is integrated in every modelled slaughter and

inspection step;

Transmission of AH hazards among animals at lairage is ignored as the time

period spent in lairage is generally short. With regard to PH, with the

example of Salmonella, cross-contamination is modelled; thereby initially

hazard-free animals can become hazard carriers.

46

Annex 3. Results and discussion by hazard

Mycobacterium bovis

M. bovis in cattle is considered in the context of this work as an AH hazard. Our

assessment has the ultimate aim of evaluating two aspects of risk posed to cattle

health by this hazard in the context of different GO inspection scenarios:

1. whether the capability of detecting lesions is different among the different GO

inspection scenarios.

2. whether the proportion of undetected TB-positive carcases in the chilling

room differs for different GO inspection strategies.

Annex 4, table 17 lists the main steps consider in the risk assessment model for this

pathogen, the input data, sources and data gaps.

Results

Lairage: Prevalence of M. bovis in cattle in the UK was assumed to be 0.5 % [16]. The

model focuses only on TB non-reactors (a fraction of the infected animals), since

reactors must undergo separated slaughter with enhanced post-mortem inspection,

which, if considered, would bias the results of the risk assessment as laid out in our

model. The actual proportion of non-reactors showing clinical signs of disease in the

UK (low grade fever, chronic intermittent hacking cough, difficult breathing,

emaciation, etc.) is considered to be low, and the model predicts that a very low

proportion of infected non-reactors can be detected before slaughter (ante-mortem

inspection). This is in line with the fact that symptoms of clinical disease, even if

present, are not pathognomonic (see annex 4, table 17), what makes identification of

infected animals more difficult.

Post-mortem inspection: Animals can have characteristic TB lesions in various

organs, but these are primarily present in the lymph nodes of the lungs (mediastinal

and bronchial) and head (mainly retropharyngeal). The proportion of infected

animals with TB lesions in bronchial, mediastinal or retropharyngeal lymph nodes

was considered moderate according to the data sources consulted, with a high

probability of detecting the lesions in bronchial or retropharyngeal inspection, and

high for inspection of mediastinal lymph nodes (tab. 9) with the current MI, i.e. with

47

incision of corresponding lymph nodes. The final probability that lesions will be

detected in the lungs or head is moderate.

After slaughtering, carcase dressing and all MI procedures have been performed, the

carcase is placed in a chilling room. Based on rejection data provided by the Food

Standards Agency the proportion of carcases of infected animals at chiller is believed

to be very low. Considering this, together with low probability the model predicts

that a negligible proportion of carcases of infected animals showing lesions only in

GO will be present at chilling (for each of the three scenarios).

Green offal inspection and alternative scenarios: In cattle older than six weeks (the

subject of this project), inspection of GO mandates visual inspection of all GO with

palpation and, if necessary, incision of the gastric and mesenteric lymph nodes. The

probability of a TB infected animal showing lesions in GO (TB granuloma in the

lymph nodes) is very low; the probabilities that these lesions are detected, if present,

by 1) current GO inspection, by 2) visual only and 3) without GO inspection were

compared. The probabilitiess for the three scenarios were very low (scenario 1) and

negligible (scenario 2 and 3), respectively (tab. 9).

Table 9. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for M. bovis

(likelihood categories: N = negligible, VL = very low, L = low, M = moderate, H = high)

STEP Prevalence (%)

Probability lesions are present

probability lesions are detected

Within-step probability

Inter-step and final probability

Infected animal at abattoir* L

LAIRAGE

AM inspection

L L VL L

POSTMORTEM

Head inspection

M H M VL

Lungs inspection

M H M N

Whole carcase inspection

N L N N

GREEN OFFAL

Scenario 1 VL

M VL N

Scenario 2

N N N

Scenario 3

N N N

CHILLING N

Sensitivity analysis

As part of the sensitivity analysis, the model was run with another initial prevalence

of infection (50 %). The probability that lesions present in an infected animal will be

detected remained the same for current and only visual GO inspection, i.e. very low

48

vs. negligible, but the total proportion of carcases carrying the hazard at chiller was

higher.

Discussion

The probability that an infected animal shows clinical signs of M. Bovis was low; it is

not surprising that our model indicated that a very low proportion of infected

animals will be detected before slaughter, i.e. during ante-mortem inspection.

Furthermore, the fact that those signs are not pathognomonic suggests that a large

majority of infected non-rectors will pass ante-mortem inspection undetected. Post-

mortem inspection is therefore the most effective way of detecting this AH hazard at

the abattoir (followed by diagnostic test confirmation).

There were differences in the capacity of detection of M. bovis lesions in the three

different GO inspection scenarios. However, the three scenarios will result in a

negligible probability that a carcase in the chilling room will carry M. bovis. This

suggests that the risk to cattle health as a consequence of this hazard is unlikely to

change if GO inspection was modified.

It is important to note that, for TB infected animals, when lesions are present in GO it

is very likely that lesions will also be present in other organ systems. Furthermore,

there is a moderate probability that lesions are present in either lymph nodes of the

head or lungs, locations for which the current MI tasks seem to have a great

efficiency of detection. In terms of a risk to AH, it is sufficient that TB lesions are

detected in one organ for further actions to be put in place. The presence of TB

lesions in several organs would be of greater importance in a risk assessment of M.

bovis as a PH hazard. This emphasizes the current requirement to inspect all body

parts and organs before the decision is taken if a carcase is fit for human

consumption.

Mycobacterium avium subsp. paratuberculosis

MAP in cattle is assessed as an AH hazard. This assessment has the ultimate aim of

evaluating two aspects of risk for the health of bovines in the context of different GO

inspection scenarios:

1. whether the capability of detecting lesions is different for different scenarios

of GO inspection.

49

2. whether the probability of having carcases infected with MAP is different for

different GO inspection scenarios

Annex 4, table 18 list the main steps consider in the risk assessment model for this


Results

Lairage: On the basis of a study conducted in south-west England [40] we assumed a

prevalence of MAP in adult cattle in the UK of 3.5 %. The proportion of infected

animals showing clinical signs of disease (chronic weight loss, emaciation, diarrhoea,

debility, etc.) at lairage is considered to be very low and, as a result, our model

predicts that a very low proportion of infected animals will be detected before

slaughter, i.e. on the basis of clinical signs.

Post-mortem inspection: lesions associated with this hazard are very often

exclusively present in GO. On occasions, lesions may be found on the dressed

carcase and its external surfaces in the form of emaciation and the muscle pits on

pressure [41]. However, the capacity of the inspection system to detect those

conditions in infected animals was considered low.

With an initial prevalence of 3.5 %, a moderate probability that an infected animal will

show lesions and the low detection probabilities (for ante-mortem inspection, carcase

and GO inspection), the final probability of a carcase carrying lesions at point of

chilling is estimated to be very low for all three GO inspection scenarios. This finding

cannot be checked against official reports in the country, given that submission of

samples for testing is not routinely performed for MAP.

Green offal inspection and alternative scenarios: In cattle within the considered age

category, GO inspection consists of visual inspection (with palpation and, if

necessary, incision) of gastric and mesenteric lymph nodes. With the probability of

infected animals showing lesions in GO (thickened and corrugated intestinal mucosa

and enlarged caecal lymph nodes) being moderate, and the probabilities of detection

of each GO inspection scenario being moderate for current and visual inspection and

negligible for absence of GO inspection, this results in a low overall capacity of

detection of infected animals for the current and visual GO inspection, and

negligible if GO inspection is not conducted (tab. 10).

50

Table 10. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for M. avium

subsp paratuberculosis (likelihood categories: N=negligible, VL=very low, L=low, M=moderate, H=high)

STEP Prevalence (%)





Infected animal at abattoir VL

LAIRAGE

AM inspection

VL M VL VL

POSTMORTEM


L H L VL

GREEN OFFAL

Scenario 1 M

M L VL

Scenario 2

M L VL

Scenario 3

N N VL

CHILLING VL


The resulting probability of detection of infected carcases did not change for any of

the GO scenarios when a risk assessment was done assuming a higher initial

prevalence of infection of 50 %. This indicates that the results of the model are not

dependent on prevalence of infection.

Discussion

Our model indicates that only a very low proportion of infected animals can be

detected before slaughter, i.e. ante-mortem inspection. The fact that that clinical signs

in infected animals are not specific for paratuberculosis suggests that the vast

majority of infected animals will pass ante-mortem inspection undetected as MAP.

Since laboratory testing is not performed routinely, post-mortem inspection is the

only way of detecting this disease in the abattoir.

Our findings indicate that GO inspection (primarily intestines) is the most important

task in detecting this hazard. The comparison of the probability that MAP lesions

will be detected within each of the three scenarios, i.e. low, low and negligible (see tab.

10), indicates the current GO inspection is a significant step in detecting this hazard,

but given that only visual inspection provides the same level of “protection” it can

be questioned the degree to which incision and palpation contribute to hazard

detection.

51

Toxoplasma gondii

T. gondii in sheep is assessed as a PH hazard. Our risk assessment has the ultimate

aim of evaluating:

1. Whether different GO inspection scenarios have a different capacity to detect

the hazard.

2. Whether the consumer’s exposure to T. gondii is greater if GO inspection is

not performed in slaughtered sheep.

Annex 4, table 19 list the main steps consider in the risk assessment model for this


Results

Lairage: Seroprevalence of T. gondii in sheep in the UK was estimated to be 48.6 % in

2009 [16]. The proportion of infected animals showing clinical signs of disease

(difficulties of breathing, fever, tremor, etc.) is very low, and this model predicts that

a negligible proportion of infected sheep can be detected during ante-mortem

inspection. This relates to the fact that these signs are not specific for toxoplasmosis.

Post-mortem inspection: Infected animals can show lesions (mostly necrosis) in

various locations, such as the lungs, heart, liver, kidneys and the carcase.

Nevertheless, the probability of an animal showing clinical signs, and specifically

these lesions, is very low. Lesions are more likely in the liver (low). In other organs a

very low or negligible proportion of all lesions will be detected (tab. 11). This suggests

that post-mortem inspection has a limited role in detecting toxoplasma infected

animals.

Green offal inspection and alternative scenarios: In small ruminants, mandatory

inspection of GO implies only visual inspection, therefore only two scenarios were

modelled: scenario 1 (traditional GO inspection) and scenario 3 (absence of GO

inspection). Animals do not tend to show lesions in GO (probability that an infected

animal shows lesions in GO, such as intestinal ulceration and changes in mesenteric

lymph nodes, is negligible). As a consequence, none of the modelled GO scenarios is

of relevance for detecting infected animals.

52

Table 11. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for

Toxoplasma gondii (likelihood categories: N = negligible, VL = very low, L = low, M = moderate, H = high)

STEP Prevalence (%)





Infected animal at abattoir M

LAIRAGE

AM inspection

VL VL N M

POSTMORTEM

Lungs inspection

VL L VL M

heart inspection

VL M VL M

liver inspection

L H L M

kidneys inspection

N N N M


N H N M

GREEN OFFAL

Scenario 1/2*

N M N M

Scenario 3

N N M

CHILLING M

* For small ruminants, current GO inspection corresponds to visual inspection.


An alternative model was created with a different initial prevalence of infection in

sheep (1 %). The final result on probability that present lesions will be detected by

current inspection of GO remained negligible.

Discussion

With a very low probability that an infected animal shows clinical signs of disease,

our model indicates that a negligible proportion of infected animals will be detected

before slaughter, i.e. ante-mortem inspection. Furthermore, the fact that those signs

are not specific for toxoplasmosis indicates that infected animals are very likely to

pass ante-mortem inspection undetected. Since laboratory testing is not performed

routinely, post-mortem inspection is the only option for detecting this disease even if

it is ineffective.

GO inspection seems to have a low ability to detect T. gondii. This is mainly due to

the fact that infected animals are very unlikely to show clinical signs in these organs.

Moreover the lesions, if present, are rather unspecific and therefore unlikely to be

associated with T. gondii by the person performing the inspection. The same applies

53

to other organs, resulting always in low, very low or negligible probabilities of

detection (see tab. 11).

Submission of samples from suspect animals does not take place routinely (VLA,

pers. comm.); therefore presence of the hazard in the animal’s tissues, including

meat, cannot be estimated reliably as a step in a consumer exposure assessment.

Considering (a) the total number of reported human cases in the UK in 2009 was 158

(which is likely to be an underestimated figure for the actual number of cases, given

that enhanced surveillance in England and Wales confirmed 422 cases in 2009) [16]

and (b) the briefly described consequences for PH in Chapter 3.3 - especially for the

group of young, old, pregnant, immune-compromised and sick (YOPIS) - the risk of

T. gondii to PH could be considered as moderate. The results suggest that GO

inspection does not have an influence on the final exposure, i.e. risk for PH (based on

a presence of hazard in carcase meat in a chilling room, as a proxy for final

exposure).

Salmonella

Salmonella in pigs is assessed as a hazard to PH. Our assessment aimed to evaluate:

1. Whether different GO inspection scenarios have different capacity of

detecting the hazard.

2. whether the consumer’s exposure to Salmonella spp. is greater if GO

inspection is not performed in the current way.

Model characteristics and assumptions

In the specific case of Salmonella spp., the hazard is not only represented by infected

pigs arriving at chilling, but healthy pigs that can become cross-contaminated during

slaughter contributing to the risk to PH. As the risk to PH arises from faecal

contamination of the surface of meat, the change in prevalence of Salmonella on the

carcase surfaces was modelled.

The risk assessment includes two extra steps at slaughter: FCI and possibility for

cross contamination. It is assumed that batches of animals from high-prevalent herds

can be detected by the accompanying food chain information (FCI) and therefore

would be slaughtered at the end of the day under a higher level of alertness. These

animals were excluded from routine slaughter at step “FCI” on the risk pathway.

54

The risk assessment pathway includes the slaughter activities, as these are known to

crucially contribute either to decreasing the prevalence of the hazard or to increase it

via cross-contamination. See figure 3 for a graphical representation of the Salmonella

risk assessment model, along with the results.

Further assumptions, input data, data sources and data gaps are presented in annex

3, table 20.

Results

Lairage: According to the results of the EFSA baseline study the prevalence of

Salmonella spp. in pigs in the UK is 21.2 % (17.8 % - 25 %) [20]. The Salmonella status

of a herd is displayed in the FCI and the proportion of animals from herds with high

intra-herd Salmonella prevalence (> 50 %) which are separated for logistic slaughter

purposes is assumed to be low. As infection with S. Typhimurium, the most frequent

isolated serovar in pigs, is usually subclinical in the considered age category the

probability that animals are detected during ante-mortem inspection and separated

from the rest of the batch is negligible. Due to the high proportion of “clean” animals

being cross-contaminated by shedders, the probability that Salmonella is present

in/on an animal upon arrival at slaughter hall is moderate.

Slaughter process: During slaughter the Salmonella prevalence (i.e. proportion of

animals carrying the hazard) changes substantially from one process to the next [43-

47]. This is in line with reports in the literature: prevalence figures of samples taken

after the respective slaughter activities are not consistent in the literature and range

from 0 % - 100 %.

To inform our risk assessment, results from several studies were compared and

average values were chosen based on the variable stated trends (see annex 2).

Scalding and singeing were identified as major steps that highly reduce the Salmonella

prevalence. Between polishing and dressing, the prevalence raises again back to

moderate level. Trimming may bring a further very low reduction. At the end of

slaughter the model assumes that Salmonella is present in/on a moderate proportion of

carcases presented to post-mortem inspection (see fig. 3).

55

Figure 3: Graphic representation of the model applied to Salmonella spp. N = Negligible, VL = Very low, L = Low, M = Moderate, H =

High. The ongoing risk for a pathway is shown in dimonds after each input step.

Probability of a carcase carrying a

hazard at chilling

56

Post-mortem inspection: Faecal contamination (both in infected and healthy

animals) and acute enteritis/enterocolitis (in infected animals) are regarded to be the

only “visual conditions” caused by Salmonella.

Only a very low percentage of carcases show lesions during visual inspection of the

whole carcase. Microscopic contamination is below the “detection limit” of a meat

inspector’s eye. For that reason the probability of a carcase being rejected at this

inspection step is negligible.

Green offal: The probability that a macroscopic lesion is present in GO is low (tab.

12). Even if the probability that these lesions will be detected by current GO

inspection is high, only a very low percentage of carcases will be rejected for reasons

of acute enterocolitis, spillage of gut content or faecal contamination of the guts.

Corrective actions by the slaughterhouse personnel will target visible lesions but will

only result in a very low reduction of the number of carcases carrying Salmonella.

The final outcome of the model is that the risk of a carcase being contaminated with

Salmonella at the entrance of the chilling room is medium. Nevertheless, the process of

chilling is known to lead to a moderate reduction of the prevalence of Salmonella on

pig carcases. For this reason, after the required hours of chilling the actual

probability of a carcase carrying Salmonella would become low (see fig. 3).

Alternative GO inspection scenarios: the model suggests that GO inspection has

the ability to detect (with low probability) visual conditions associated with

Salmonella. Nevertheless, the different GO inspection scenarios, including absence of

inspection, result in no substantial difference in the Salmonella prevalence at the

chilling room (it remains moderate for the three scenarios). This is related to fact that

detection of the conditions associated with Salmonella (faecal contamination and

enteritis) will not result in rejection of the carcase.

It is likely that a lower number of acute enterocolitis cases would be detected if

lymph nodes were not palpated [48]. Without GO inspection enterocolitis will not be

detected at all. But as the number of enterocolitis cases presented at post-mortem is

generally very low and the probability that carcases are rejected if lesions are seen in

their GO is negligible, the combined probability of the presence of a macroscopic

lesion, its detection by the meat inspector and the ensuing condemnation is negligible.

57

Table 12. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for

Salmonella (likelihood categories: N = negligible, VL = very low, L = low, M = moderate, H = high)

STEP Prevalence (%)





Infected animal at abattoir L

LAIRAGE

FCI

H L L L

AM inspection

N L N L

cross contamination*

M* M

SLAUGHTER PROCESS

stunning - killing -bleeding*

N* M

scalding

H L

Dehairing*

L* L

Singeing

H VL

Polishing-washing*

M* L

belly opening - evisceration*

M* M

splitting - dressing*

N* M

trimming

VL M


VL H VL M

GREEN OFFAL

Scenario 1 L

H L M

Scenario 2

H L M

Scenario 3

N N M

CHILLING M

*steps that increase presence of hazard in carcase


Within individual batches of pigs, rates of isolation of Salmonella can range from 0 %

to 71.4 % from intestinal contents, and from 0 % to 100 % on carcases [45]. Several

studies supported the finding that there is an enormous variation in Salmonella

prevalence on different sampling days and even a significant difference between

samples taken from morning or afternoon production [46]. Therefore, the input

values for animal prevalence (low) and the proportion of contaminated/infected

animals upon arrival at the slaughter-hall (moderate) were changed from low to very

low, moderate and high in the sensitivity analysis. In all three scenarios the prevalence

at chilling remained low. This finding can be explained by the fact that the model

assumes that scalding and singeing will reduce any initial prevalence to a low level

and that a high number of carcases will be contaminated after dehairing and

evisceration.

58

Discussion

In 2007, the total PH costs for a family with a case of S. Typhimurium were

estimated to be as high as £ 14,700 per case; the annual case number in the UK was

predicted to be around 600 (with an underreporting of 1:3 or even 1:4) [17, 19]. In

addition to such direct human costs in terms of illness and suffering, the association

of food poisoning outbreaks with pork products has major economic impacts on the

pork processing industry [43].

Several studies reported findings of different patterns of Salmonella serotypes after

various stages during pork slaughter [43, 45]. This interesting finding implies that

carcases get contaminated with residual microflora present in the abattoirs during

the slaughter process [49]. Salmonella spp. already present on the skin of live animals

are less likely to survive scalding and singeing [50]. In the recently published

Quantitative Microbiological Risk Assessment (QMRA) on Salmonella in Slaughter

and Breeder pigs [47] the prevalence increases to 100 % after evisceration,

attributable to the so called house flora, contaminating every carcase with a small

amount of Salmonella spp. Without doubt the probability of detecting this type of

contamination at post-mortem inspection is very low, resulting in a high risk of storing

Salmonella-positive carcases in the chilling room. Even if the load of bacteria is

confined to a very small number of cfu and might not pose a PH risk if consumed

immediately, poor management of hygiene and product control in the consecutive

steps in the food chain can lead to bacterial growth. Therefore the results of

slaughterhouse prevalence data should be interpreted with caution.

Scientific studies in the past concluded that the risk to PH will remain as long as

Salmonella-positive animals enter abattoirs, even if the slaughter process is carried

out according to stringent codes of good manufacturing practices [50]. The results

described above highlight that the current control strategies carried out, including

MI, may be able to decrease the risk to PH at this stage of the food chain, but are

insufficient to fully remove the risk.

Classical Swine Fever

CSF is assessed as a hazard to AH. This assessment aimed to evaluate two aspects of

risk to pig health:

1. whether a difference exists between the three scenarios of GO inspection in

their capability to detect lesions associated with CSF.

59

2. whether the exposure of susceptible livestock to CSFV from carcases of

infected pigs varies for different GO inspection scenarios;

Disease characteristics and assumptions

Clinical signs in pigs infected with CSF are usually very unspecific; therefore it is

difficult to diagnose the disease if only one single pig is infected, as the list of

differential diagnoses is long [25]. Therefore, CSF is often described as a herd

disease: clinical and pathological signs become more obvious if the herd as a whole

is investigated [51, 52]. To take account of this important fact, the risk questions were

assessed for two different situations:

Situation 1 - “low prevalence”: a single pig out of a batch of 50 animals is

infected (prevalence is 2%);

Situation 2 - “high prevalence”: ten pigs out of a batch of 50 animals are

infected (prevalence is 20%).

As CSF is not present in the UK, the following background scenario was assumed:

Finisher pigs have been infected on a farm approximately 30 days before being sent

to slaughter with a moderately virulent CSF strain. All animals are CSF-positive, but

do not necessarily show lesions.

Further assumptions, input parameters, data sources and data gaps are listed in

annex 4, table 21 (situation 1) and table 22 (situation 2).

Results

Lairage: CSF-positive animals can show a range of clinical symptoms that can be

detected during ante-mortem inspection. The probability that these animals will be

detected at ante-mortem inspection is low, with a large amount of them likely to be

sent for routine slaughter3.

Post-mortem inspection:

A variety of lesions ptoduced by CSF can be seen during visual inspection of the

carcase, head, lungs, spleen, heart, liver, kidneys, pleura, peritoneum and GO.

Lesions will not necessarily be present in more than one organ system. The post-

3 This assumes that, although lesions may be detected in few animals at AM inspection, CSF will not

be suspected. In the case of CSF being suspected, none of the animals from that batch will be

processed normally. Our assessment does not consider this scenario.

60

mortem MI tasks have only low or very low probability of detection of the hazard.

As a consequence, mainly due to the fact that the modelled prevalence is very low,

the probability of the hazard being present at chiller is very low.

Green offal:

Examples of lesions in GO are enlarged lymph nodes, dry or watery faecal contents

in colon or jejunum, oedema of the mesocolon, a hyperaemic intestinal tract and

fibrin in the abdomen. In a moderate proportion of cases, at least one of these

pathological conditions will be present. If a lesion is present, the probability that it

will be detected is moderate. As a result, GO inspection (current and visual)

contributes to the detection of CSF infected animals (low), whereas total absence of

GO inspection does not (negligible). Nevertheless, the probability of carcases carrying

the hazard at chilling is not influenced by the type of GO inspection carried out,

mainly due to the fact that findings at GO are very unlikely to result in rejection of

the whole carcase.

Situation 1 (single animal): When the model was run for a batch formed of only one

infected pig, the probability that a CSF-contaminated carcase was present in the

chiller was high with the probability of this carcase showing lesions being low (it is

assumed that all abnormalities noticed by meat inspectors are trimmed

consecutively). If run for a batch of 50 animals, the overall probability of having a

CSF- positive carcase in the chiller was low, and the probability of a carcase showing

lesions remained low.

Situation 2 (group): if ten out of 50 pigs in lairage were CSF-positive, the probability

that these pigs show at least one clinical sign was high (tab. 14). With a moderate

probability of detection during ante-mortem and high probability that suspicious

animals will be separated, only a small (low) number of cases will be allowed to be

slaughtered routinely. The probability that lesions will be present and detected in

organs other than GO and that the carcases will be rejected are high. At GO

inspection a high proportion of guts show lesions and in a moderate number of cases

these findings will lead to the rejection of the carcase.

The probabilities of a carcase a) carrying the CSF-Virus or b) showing lesions

associated with CSF at the point of chilling are both very low.

61

Table 13.Situation 1. Summary of the intermediate (green cells) and final results (pink cells) of the risk model

for classical swine fever virus (likelihood categories: N=negligible, VL=very low, L=low, M=moderate, H=high).

STEP Prevalence (%)






LAIRAGE

AM inspection

M M L VL

POSTMORTEM

head inspection

M M L VL

Lungs inspection

M M L VL

pleura inspection

L M L VL

spleen inspection

L M L VL

heart inspection

VL M VL VL

liver inspection

L M L VL

kidneys inspection

M M L VL


VL M VL VL


L M L VL

GREEN OFFAL

Scenario 1 M

M L VL

Scenario 2

M L VL

Scenario 3

N N VL

CHILLING VL

Alternative GO inspection scenarios: According to expert opinion, the probability is

very low that lesions are only noticeable by palpation of the gastric and mesenteric

lymph nodes if GO is affected. Therefore the model predicts the same probability of

detection of a lesion in GO (moderate) for the alternative GO inspection and for visual

only inspection. However, if GO inspection is absent and no lesions are detected, the

final result of the model will not change – the prevalence of CSF-positive carcases in

the chiller is still very low (single pig)/low (group).

Sensitivity analysis:

A sensitivity analysis was made to estimate the proportion of missed cases if the

sensitivity of MI, i.e. the probability that lesions will be detected, would change from

moderate to high or low. With a high detection rate for every MI task, a high number of

lesions could be detected, but nevertheless the prevalence of CSF-positive carcases at

chilling would not decrease further from low (single pig) and very low (group) if the

total condemnation rate were to remain very low.

62

Table 14.SCENARIO 2. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for classical swine fever virus (likelihood categories: N=negligible, VL=very low, L=low, M=moderate, H=high).

STEP Prevalence (%)





Infected animal at abattoir L

LAIRAGE

AM inspection

H M M VL

POSTMORTEM

head inspection

M M L VL

Lungs inspection

H M M N

pleura inspection

M M L N

spleen inspection

M M L N

heart inspection

L M L N

liver inspection

M M L N

kidneys inspection

M M L N


L M L N


M M L N

GREEN OFFAL

Scenario 1 H

M M N

Scenario 2

M M N

Scenario 3

N N N

CHILLING N

If lesions would only be detected with a low probability, then a moderate number of

lesions could be detected with the current GO inspection and with visual inspection

of GO; a difference can be noticed for scenario 3: in absence of GO inspection, the

proportion of detected lesions would decrease to low.

Discussion

One of the purposes of MI is to identify exotic contagious livestock diseases,

including CSF, among others. The results of our risk model indicate that infected

animals can be to a large extent detected with ante- and post-mortem inspection.

An interesting finding is that the probability of having a CSF-positive carcase, or a

carcase with lesions associated with CSF, at point of chilling is in all three GO

scenarios very low, irrespectively of whether CSF causes lesions in GO with a

moderate (situation 1) or even with a high (situation 2) likelihood. The reason for this

is that, in the model, a low (situation 1)/moderate (situation 2) number of infected pigs

with lesions is already detected at ante-mortem. In addition, the likelihood that a pig

shows lesions exclusively in GO is very low. Therefore, animals with lesions in GO

63

are likely to have been already detected with other MI tasks earlier on in the process.

As a consequence the final proportion of CSF-positive carcases in the chiller does not

change substantially, whether or not GO is inspected. This finding is supported by a

Danish risk assessment which concluded that the ability to identify exotic contagious

diseases is not affected if the stomach and the intestines are visually inspected

instead of palpating intestinal lymph nodes, as the infection usually results in lesions

in other organs in addition to the ones in the intestinal lymph nodes [48].

Abdominal and inguinal hernia

In this model hernias in pigs are considered from an AW perspective. This

assessment has the aim to evaluate:

1. whether the capability of detecting lesions associated with this hazard is

different for different GO scenarios.

In this context the probability of a carcase presenting with lesions associated with

hernia at the point of chilling is used as a proxy for a lack of identification, and

therefore consequent reporting, of this AW issue;

Model assumptions, input data, data sources and data gaps are presented in annex 4,

table 23.

Results

Lairage: The prevalence of abdominal and inguinal hernias in the UK is assumed to

be very low. A moderate part of pigs with hernia will be detected during ante-mortem,

but given that it is very unlikely that this finding will lead to a rejection of the whole

carcase, the probability that an animal will not be sent to routine slaughter as a

consequence of the detection is negligible

Post-mortem inspection: The probabilities that lesions are present and detected

during visual inspection of the whole carcase are high (tab. 15) as the hernia sac is

usually visible from the inside of the abdominal wall. Hernias can sometimes lead to

peritonitis and strangulation, and eventually to infection of the trapped gut. For this

reason, a moderate number of macroscopic lesions could be present on the

peritoneum; they will be spotted with a high probability but only lead to rejection of

the carcase in a low proportion of cases.

64

Green offal: With GO, the probability that a lesion is present during inspection is

high as is the detection probability (tab. 15). Rejection of the whole carcase due to

lesions in GO is the consequence in a negligible proportion of cases as normally only

GO will be rejected in this situation. In addition, such incidents will be reported to

the carcase inspector so that they check for peritonitis or faecal contamination in case

of gut rupture.

After having passed post-mortem inspection, the probability is very low that a carcase

presents with lesions associated with hernia. Lesions associated with hernias

(pouches in carcase wall, peritonitis, altered intestine) detected during post-mortem

inspection are assumed to be trimmed; as a matter of these rectifications only a

negligible proportion of carcases will present with lesions at point of chilling.

Alternative GO inspection scenarios: No literature was found that describes a

special link between gastric and mesenteric lymph nodes and hernia. Hence, our

model suggests no difference in the probability of a carcase presenting with lesions

whether the current GO inspection is carried out or whether GO is only visually

inspected. Given that lesions on the carcase wall and in the peritoneum are highly

likely to be detected during visual inspection of the carcase and peritoneum,

potentially missed lesions in GO do not result in a change of the ultimate prevalence

of lesions at point of chilling.

Table 15. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for Hernia


STEP Prevalence (%)






LAIRAGE

AM inspection

H M M N

POSTMORTEM


M H M N


H H H N

GREEN OFFAL

Scenario 1 H

H H N

Scenario 2

H H N

Scenario 3

N N N

CHILLING N

65

Sensitivity analysis: Changes in neither the probability that lesions will be detected

during GO inspection (high) nor the prevalence of peritonitis (moderate) resulted in a

change of the ultimate prevalence of lesions. This can be explained by the fact that in

its application to hernia the model relies strongly on two factors: “probability that a

lesion will be detected by visual inspection of the whole carcase” and “probability

that a lesion will be detected by visual inspection of the peritoneum”. As long as a

high proportion of lesions will be detected when the surfaces of a carcase are

inspected only a negligible number of lesions will be missed. Should only a moderate

number of lesions be detected with inspection of the whole carcase, the prevalence of

lesions at chilling will rise from negligible to very low.

Discussion

The application of the risk model to an AW condition like hernia shows that if the

contribution(s) of a single or two MI tasks to detect a lesion (or hazard) are already

high, the remaining MI task will play a minor role in raising the overall capability to

detect signs of compromised animal wellbeing or disease.

Prevalence estimates from literature [31, 32, 34] and expert elicitation do not confirm

the low rejection rate recorded in data provided by the Food Standards Agency. A

possible explanation for this apparent underreporting is given in a Canadian study

that suggests that, given that over 50 % of pigs with large hernias will be condemned

for peritonitis, carcase lesions be recorded as “peritonitis” at the abattoir [31]. By

doing so a present undesired condition is communicated, but the origin of the

problem is not revealed, limiting its value to detect and act upon AW issues.

Besides the discussion on economic losses due to rejection of carcases, welfare is an

important consideration in the decision made concerning the care and production of

young pigs with hernias. The welfare of pigs with severe adhesions on the intestines

and skin may be significantly compromised. [34]. According to literature some

degree of fibrin adhesion is evident in all cases [34]. Inspectors should be observe for

these adhesions, visible at slaughter, in order to increase the protection of AW.

It is unlikely that large hernias with complications, such as strangulation of intestine,

abscessed hernia sac or peritonitis will not be detected at the abattoir. Again,

inspection has a great value in the identification of this AW concern. Nevertheless, if

these findings are not appropriately documented and reported, MI will not have any

impact on protecting AW.

66

Tail biting

Tail biting in pigs is assessed as an AW hazard. This assessment aimed to evaluate:

1. whether the capability of detecting the lesion associated with this hazard is

different for the GO scenarios considered.

Model characteristics and assumptions

Animals with healed tails are not considered, only those where lesion are still

present. In this context the hazard is “being the victim of tail biting with visible

lesions”

Further assumptions, input data, data sources and data gaps are listed in annex 4,

table 24.

Results

Lairage: The prevalence of tail biting was assumed to be very low. The probability

that tail bite lesions will be noticed during ante-mortem inspection is high, but the

proportion of tail bitten pigs that will be rejected from further slaughter is assumed

to be negligible (tab. 16).

Post-mortem inspection: Lesions can be seen during visual inspection of the whole

carcase and, additionally, in the lungs [53]. The probabilities that lesions are present

and that these are detected during visual carcase inspection are both high. Tail bite is

associated with a moderate proportion of carcases being condemned. In the lungs

abscesses will be present only in a low proportion of tail bitten animals, but a high

percentage of these will be rejected.

The model predicts that a high proportion of tail bites will be found during post-

mortem, but only a low proportion of these will be trimmed after this condition has

been detected (in addition to the moderate number of rejected carcases).

Green offal: No literature was found describing the presence of abscesses in GO as a

consequence of tail bites. The body parts and organs mostly affected are the carcase,

including the tail and spine, and the lung; rarely abscesses can be found in the heart,

liver, umbilicus, head and peritoneum [36, 39]. Therefore GO inspection plays a

negligible role in the detection of tail bite lesions. As a result, modification of GO

inspection has no effect on the prevalence of carcases with lesions in the chiller.

67

Table 16. Summary of the intermediate (green cells) and final results (pink cells) of the risk model for tail biting


STEP Prevalence (%)






LAIRAGE

AM inspection

H H H N

POSTMORTEM

Lungs inspection

L H L N


H H H N

GREEN OFFAL

Scenario 1 N

N N N

Scenario 2

N N N

Scenario 3

N N N

CHILLING N

Sensitivity analysis: Considering prevalence close to 100% (all animal at slaughter

presenting with tail biting) the model predicts that approximately every second case

would lead to the carcase being condemned. Therefore the initial high proportion of

tail bitten pigs at chilling can be reduced to moderate.

The risk of having missed carcases with tail bites can only be reduced to a negligible

risk if the initial prevalence is lower or if a high proportion of carcases detected

during visual inspection of the whole carcase were rejected.

Discussion

MI tasks seem to have a good capacity to detect hernias, with the exception of GO

inspection. Lesions on these organs as a consequence of tail biting are extremely

unlikely, and therefore the contribution of GO inspection to the reduction of risk to

AW is negligible.

An interesting finding was that only a minor part of all tail bites detected during

post-mortem inspection may actually be recorded. Rejection data provided by the

Food Standards Agency showed that tail bite is only reported in 1.7 per 10,000 pigs.

Literature and expert opinion suggested a much higher proportion of severe tail bite

wounds and secondary complications [36, 39, 53, 54] which often result in

abscessation. Hence, it is likely that the ultimate reason for condemnation may often

be reported as pyaemia or multiple abscessations without being associated with tail

bite injuries. This translates into underreporting of tail biting at slaughter.

68

Annex 4 – Model assumptions, input data, data sources and data gaps.

Table 6: Input data, assumptions, likelihood estimates and data sources for the model for M. bovis in cattle.

This hazard is evaluated in relation to its animal health risk (MI = meat inspection, Mod. = module; LHE =

likelihood estimate according to table 1: N = Negligible, VL = Very low, L = Low, M = Moderate, H = High).

Mod. Step Inputs, assumptions and main data gaps LHE Source

Lair

age

Arrival Prevalence of hazard in animal’s population

0.5% Defra, 2010

Proportion of diseased animal’s that are not TB

reactors

L based on average

Se of tests (from

multiple studies)

Food chain

information

Not relevant as the focus lies on animals which are

not reactors

- assumption

Cross-

contamination

Not applicable to this hazard in any stage - -

Ante-mortem

inspection

Proportion of animals showing clinical signs L Seth et al., 2009

Sensitivity and specificity of AM L author’s estimate

Slau

ghte

rin

g Stunning to

carcase in

chilling room

None of steps in slaughter process is relevant for

the presence of hazard on carcase or offal

- assumption

Probability that lesions are present in carcase

and/or offal

M [60] FSA, 2009

Po

st m

ort

em in

spec

tio

n

Red offal

inspection

Lungs (related to current MI): - -

Probability that lesion is present in lung

parenchyma

VL FSA, 2009

Probability that lesion can be detected in lung

parenchyma

M Liebana et al., 2008

Probability that lesion is present in mediastinal

lymph nodes

M FSA, 2009

Probability that lesion can be detected in

mediastinal lymph nodes

H FSA, 2009

Probability that lesion is present in bronchial lymph

nodes

L FSA, 2009

Probability that lesion can be detected in bronchial

lymph nodes

H FSA, 2009

Head

inspection

Head (related to current MI): - -

Probability that lesion is present in retropharyngeal

lymph nodes

M FSA, 2009


retropharyngeal lymph nodes

H FSA, 2009

Whole carcase

inspection

(external

surfaces)

Probability that lesion is present on external

surfaces of dressed carcase

N author’s opinion

Probability that lesion can be detected on external


L author’s opinion

69

Green offal

inspection

Probability that lesion is present in mesenteric

lymph nodes

VL FSA, 2009


mesenteric lymph nodes with current MI

M FSA, 2009


mesenteric lymph nodes with only visual MI


Oth

er

Chilling room Probability that hazard is present in a chilling room

(carcase, offal)

VL assumption

(supported by FSA,

2009)

Table 7: Input data, assumptions, likelihood estimates and data sources for the model application to MAP in

cattle. This hazard is evaluated in relation to its animal health aspect (MI = meat inspection, Mod. = module;

LHE = likelihood estimate according to table 1: N = Negligible, VL = Very low, L = Low, M = Moderate, H = High).


Lair

age

Arrival Prevalence of hazard in animal’s population 2.6-

3.5%

Cetinkaya et al.,

1996

Proportion of animals older than 3 years M author’s

approximation

based on

Cattlebook in 2008

( Defra)

Food chain

information

Detection of detected animal based on FCI L assumption

Cross

Contamination


Ante-mortem

inspection

Proportion of animals showing clinical signs VL University of

Reading, 2003

Sensitivity and specificity of AM M author’s opinion

Slau

ghte

r

Stunning to

carcase in

chilling room



- assumption


and/or offal

M Buergelt et al.,

1978

Po

st m

ort

em in

spec

tio

n

Whole carcase

inspection

(external

surfaces)

Probability that lesion is present on external


L Buergelt et al.,

1978

Probability that lesion can be detected on external


H expert opinion

Green offal

inspection

Probability that lesion is present in stomach and

intestines

M Buergelt et al.,

1978

Probability that lesion can be detected in stomach

and intestines by current MI

M expert opinion

Probability that lesion can be detected in stomach

and intestines by only visual MI

M expert opinion

70

Probability that lesion is present in mesentery

M Buergelt et al.,

1978


mesentery by current MI

M expert opinion


mesentery by only visual MI

M expert opinion


lymph nodes

M Buergelt et al.,

1978


mesenteric lymph nodes by current MI

M expert opinion


mesenteric lymph nodes by only visual MI

M expert opinion

Oth

er


(carcase, offal)

data

gap

-

Table 8: Input data, assumptions, likelihood estimates and data sources for the model application to

Toxoplasma gondii in sheep. This hazard is evaluated in relation to its public health aspect (MI = meat

inspection, Mod. = module; LHE = likelihood estimate according to table 1: N = Negligible, VL = Very low,

L = Low, M = Moderate, H = High).


Lair

age

Arrival Prevalence of hazard in animal’s population (%) 48.6 Defra, 2010

Food chain

information

Not relevant for this hazard - assumption

Cross

Contamination


Ante-mortem

inspection

Proportion of animals showing clinical signs VL expert opinion

Sensitivity and specificity of AM VL expert opinion

Slau

ghte

r

Stunning to

carcase in

chilling room



- assumption


and/or offal

VL Radostits et al.,

2006

Po

st m

ort

em in

spec

tio

n

Red offal

inspection

Lungs (with current MI): - -

Probability that lesion is present in lung

parenchyma

VL expert opinion

Probability that lesion can be detected in lung

parenchyma

L expert opinion

Probability that lesion is present in mediastinal

lymph nodes



mediastinal lymph nodes


71

Heart (with current MI): - -

Probability that lesion is present in myocardium VL expert opinion


myocardium

L expert opinion

Liver (with current MI): - -

Probability that lesion is present in liver

parenchyma

L expert opinion

Probability that lesion can be detected in liver

parenchyma

H expert opinion

Kidney (with current MI):

Probability that lesion is present in kidney

parenchyma

N expert opinion

Probability that lesion can be detected in kidney

parenchyma

M expert opinion

Green offal

inspection

Probability that lesion is present in intestines N expert opinion


intestines by current MI

M expert opinion


lymph nodes

N expert opinion


mesenteric lymph nodes by current MI

M expert opinion

Oth

er


(carcase, offal)

data

gap

-


Salmonella spp. in pigs. This hazard is evaluated in relation to its public health aspect (MI = meat inspection,

Mod. = module, PM = post-mortem, LHE = likelihood estimate according to table 1: N = Negligible, VL = Very

low, L = Low, M = Moderate, H = High).


Lair

age

Arrival Animal prevalence (lymph nodes) 21.2

%

EFSA, 2008

Check FCI and

selection of

animal for

routine

slaughter

The probability that hazard will be detected with

FCI check is high as Salmonella status of farm is

reported

H

All herds with an intra-herd prevalence >50 %

(meat juice sample) will be slaughtered separately

(logistic slaughter - slaughtered at the end of the

day)

- Assumption,

supported by ZNCP

Corrective action: Probability that animal will be

slaughtered separately

L VLA, 2010; BPEX,

2008

72

Probability that animal is subject to routine

slaughter (and not separated)

H Assumption

Lairage - Cross

contamination/

infection

Probability that cross-contamination occurs H Assumption (is

associated to initial

prevalence)

If cross-contamination occurs, how many animals

will be contaminated in addition

M

Ante-mortem

inspection and

selection of

animals

Probability that clinical sign is present (for

septicaemia or acute enterocolitis)

N Expert opinion

Probability that hazard will be detected during

ante-mortem inspection - Sensitivity of inspection

L Expert opinion


separated

N Author’s opinion

Slau

ghte

r

Stunning to

presenting of

carcase to PM

The input values for the slaughter process were estimated based on results

presented in a range of scientific publications: Berends et al., 1996; Bolton et al.,

2002; Davies et al., 1999; EFSA, 2010 (data of four Member States of the

European Union), Gerats et al., 1981[61]; Pearce et al., 2004 and TEAGASC, 2010.

Prevalence figures of samples taken after the respective slaughter process,

proportional increase or reduction of contaminated carcases and the population

attributable fraction figures of these studies were collected. As the study designs

and the sampling protocols varied greatly, the collected figures were compared in

the light if trends can be observed ( process, or combination of processes, is

described to lead to an increase or reduction of hazard prevalence on the

carcase).

- Slaughter processes that were described in several publications as being the

“main” step/having the highest impact on the hazard prevalence or changed

the hazard prevalence by more than 100 % (prevalence doubled or halved),

were estimated as high;

- Slaughter processes that were described in several publications to be capable

to change the hazard prevalence significantly (but less than by 100 %) or only

were mentioned in one publication as main process were estimated as

moderate;

- Slaughter processes that were described to have in general the capacity to

reduce or increase, but only to a limited extend, were estimated as low.

- Slaughter processes that are capable to reduce hazard prevalence, but only

target a small number of carcases, were estimated as very low;

- Slaughter processes that were not mentioned at all were estimated as having

a negligible impact on the hazard prevalence.

Change(+) in probability that hazard is present

in/on carcase after stunning, killing and bleeding

N Estimation as

explained in cell

73

Change(-) in probability that hazard is present in/on

carcase after scalding

H above


in/on carcase after dehairing

L

Change(-) in probability that hazard is present in/on

carcase after singeing

H


in/on carcase after polishing/washing

M


in/on carcase after belly opening and evisceration

M

Change(+) in probability that hazard is present on

carcase after washing, cutting of breast bone, pluck

removal, splitting and dressing

N

Change(-) in probability that hazard is present on

carcase after trimming of contamination before

carcase is presented to PM.

VL

Po

st-m

ort

em in

spec

tio

n

All MI tasks For all probabilities that macroscopic lesion is

present in organ only lesions associated with

Salmonella are considered (acute enterocolitis or

faecal contamination)

- Assumption

WHOLE

CARCASE

(EXTERNAL

SURFACES)

Probability that macroscopic lesion is present in this

organ (-system)

VL FSA, 2009; expert

opinion

Probability that lesion will be detected - Sensitivity

of inspection

H Expert opinion

Corrective action: Probability that whole carcase

will be condemned

VL FSA, 2009; expert

opinion

GREEN OFFAL

(GO) inspection

Probability that macroscopic lesion is present in GO L FSA, 2009; expert

opinion

GO inspection

Scenario 1

Probability that lesion will be detected by current

green offal inspection

H Expert opinion


will be condemned

VL Expert opinion

GO inspection

Scenario 2

Proportion of missed lesions if lymph nodes are not

palpated

L Expert opinion

Probability that lesion will be detected by only

visual green offal inspection

H Expert opinion


will be condemned

VL Expert opinion

GO inspection

Scenario 3

Probability that lesion will be detected without




will be condemned


Oth

er Laboratory

testing

Probability that a sample is taken for further

laboratory diagnosis

VL Defra and VLA,

pers. comm.;

74

expert opinion

Probability that hazard will be detected during the

act of sampling - Sensitivity of MI task



will be condemned after sampling


Carcase

rectification

after PM

All lesions that are detected will be trimmed, but

only lesions present on whole carcase, peritoneum

and pleura are understood as lesions on carcase

(and will therefore lead to a reduction of lesion

prevalence on the carcase)

- Assumption

Chilling Change of prevalence on carcase through chilling:

the amount of inactivation is dependent on the

temperature and time duration.

M Author’s opinion

Hazard is present as long a carcase is in chiller,

which is contaminated with Salmonella on its

surface.

- Assumption

Table 10: Input data, assumptions, likelihood estimates and data sources for the model

application to Classical Swine Fever in pigs. Situation “single pig”: the prevalence is

assumed to be 2 % (one infected pig in a batch of 50 pigs). This hazard is evaluated in

relation to its animal health aspect (MI = meat inspection, Mod. = module, PM = post-

mortem, LHE = likelihood estimate according to table 1: N = Negligible, VL = Very low, L =

Low, M = Moderate, H = High).


Lair

age

Arrival Animal prevalence 2 % Assumption for

purpose of

modelling

Only an animal that shows a clinical signs or

pathological lesions will be detected with MI

- Assumption

Check FCI and

selection of

animal for

routine

slaughter

Probability that hazard will be detected with FCI

check - Sensitivity of inspection




H Assumption

Lairage - Cross

contamination/

infection

Time between lairage and slaughter is too short for

the CSFV to manifest in animal and develop lesions

N Assumption

Ante-mortem

inspection and

Probability that clinical sign is present M Elbers et al., 2002

Probability that hazard will be detected during M Expert opinion

75

selection of

animals

ante-mortem inspection (Probability to detect at

least one clinical sign if pig presents at least one

clinical sign).

Every animal recognized as positive animal will be

excluded from routine slaughter

- Assumption


separated

M Expert opinion

Slau

ghte

r Stunning to

presenting of

carcase to PM

Slaughter process has no influence on hazard

prevalence

- Assumption

Po

st-m

ort

em in

spec

tio

n


present in organ only lesions caused by CSF or a

secondary bacterial infection are considered

- Assumption

As no data from recent years were available the

assumption was made that the probability of

detection of macroscopic lesion is for all MI tasks

(except GO) moderate

M Assumption

WHOLE

CARCASE

(EXTERNAL

SURFACES) (V)


organ (-system)

L Elbers et al, 2003


will be condemned

L Author’s opinion

(due to dermal

petechial

haemorrhages)

HEAD Probability that macroscopic lesion is present in this

organ (-system)

M Elbers et al, 2003


will be condemned

VL Author’s opinion

LUNGS Probability that macroscopic lesion is present in this

organ (-system)



will be condemned


SPLEEN


organ (-system)



will be condemned


Heart Probability that macroscopic lesion is present in this

organ (-system)

VL Elbers et al, 2003


will be condemned


Liver Probability that macroscopic lesion is present in this

organ (-system)


76


will be condemned


KIDNEYS


organ (-system)



will be condemned


PLEURA


organ (-system)



will be condemned


PERITONEUM


organ (-system)

VL Elbers et al, 2003


will be condemned


GREEN OFFAL

(GO) inspection

Probability that macroscopic lesion is present in GO M Elbers et al, 2003

Probability that macroscopic lesion is only present

in GO

VL Expert opinion

GO inspection

Scenario 1



M Assumption


will be condemned


GO inspection

Scenario 2

Probability that lesion in GO cannot be seen but

palpated

N Expert opinion





will be condemned


GO inspection

Scenario 3





will be condemned


Oth

er

Laboratory

testing

The probability that a sample is taken for further

laboratory diagnosis was assumed to be

proportional to the rejection rate

VL Assumption



M Assumption

Corrective action: The probability that whole

carcase will be condemned after sampling is VL as

carcases will be rejected for reason of finding in PM

and not due to the act of sampling per se.


Carcase

rectification



- Assumption

77

after PM and pleura are understood as lesions on carcase



Chilling Change of prevalence/load in/on carcase through

chilling


Table 11: Input data, assumptions, likelihood estimates and data sources for the model application to Classical

Swine Fever in pigs. Situation “herd”: the prevalence is assumed to be 20 % (ten infected pigs in a batch of 50

pigs). This hazard is evaluated in relation to its animal health aspect (MI = meat inspection, Mod. = module, PM

= post-mortem, LHE = likelihood estimate according to table 1: N = Negligible, VL = Very low, L = Low,

M = Moderate, H = High).


Lair

age

Arrival Animal prevalence 20 % Assumption for

purpose of

modelling



- Assumption

Check FCI and

selection of

animal for

routine

slaughter






H Assumption

Lairage - Cross

contamination/

infection

Time between lairage and slaughter is too short for

the CSFV to manifest in animal and develop lesions

N Assumption

Ante-mortem

inspection and

selection of

animals

Probability that clinical sign is present H Elbers et al., 2002



least one clinical sign if pigs present at least one

clinical sign).

M Expert opinion

Every animal recognized as positive animal will be

excluded from routine slaughter

- Assumption


separated

H Expert opinion

Slau

ghte

r Stunning to

presenting of

carcase to PM


prevalence

- Assumption

Po

st-m

ort

em

insp

ecti

on


present in organ only lesions caused by CSF or a

secondary bacterial infection are considered

- Assumption

As no data from recent years were available the

assumption was made that the probability of

M Assumption

78

detection of macroscopic lesion is for all MI tasks

(except GO) moderate

WHOLE

CARCASE

(EXTERNAL

SURFACES)


organ (-system)



will be condemned


(due to dermal

petechial

haemorrhages)

HEAD Probability that macroscopic lesion is present in this

organ (-system)



will be condemned


LUNGS Probability that macroscopic lesion is present in this

organ (-system)

H Elbers et al, 2003


will be condemned


SPLEEN


organ (-system)



will be condemned


Heart Probability that macroscopic lesion is present in this

organ (-system)



will be condemned


Liver Probability that macroscopic lesion is present in this

organ (-system)



will be condemned


KIDNEYS


organ (-system)



will be condemned


PLEURA


organ (-system)



will be condemned


PERITONEUM


organ (-system)



will be condemned


GREEN OFFAL

(GO) inspection

Probability that macroscopic lesion is present in GO H Elbers et al, 2003

Probability that macroscopic lesion is only present VL Expert opinion

79

in GO

GO inspection

Scenario 1



M Assumption


will be condemned


GO inspection

Scenario 2


palpated

N Expert opinion





will be condemned


GO inspection

Scenario 3





will be condemned


Oth

er

Laboratory

testing

The probability that a sample is taken for further

laboratory diagnosis was assumed to be

proportional to the rejection rate

M Assumption



H Assumption

Corrective action: The probability that whole

carcase will be condemned after sampling is VL as

carcases will be rejected for reason of finding in PM

and not due to the act of sampling per se.


Carcase

rectification

after PM






- Assumption


chilling


80


abdominal and inguinal hernia in pigs. This hazard is evaluated in relation to its animal welfare aspect

(MI = meat inspection, Mod. = module, PM = post-mortem, LHE = likelihood estimate according to table 1:

N = Negligible, VL = Very low, L = Low, M = Moderate, H = High).


Lair

age

Arrival Animal prevalence 0.7% Thaller et al., 1996;

Keenliside, 2006;

Partlow et al.,

1993; expert

opinion



- Assumption

Check FCI and

selection of

animal for

routine

slaughter






H Assumption

Lairage - Cross

contamination/

infection

Not applicable to animal welfare hazards Assumption

Ante-mortem

inspection and

selection of

animals

All herniated animals carry a lesion as hernia is a

lesion per se.

- Assumption




clinical sign).

M FSA, 2009; Expert

opinion


separated

N FSA, 2009

Slau

ghte

r Stunning to

presenting of

carcase to PM


prevalence

- Assumption

Po

st-m

ort

em in

spec

tio

n


present in organ only lesions associated with

hernias are considered

- Assumption

WHOLE

CARCASE

(EXTERNAL

SURFACES)


organ (-system)

H Expert opinion


of inspection

H Author’s opinion


will be condemned


PERITONEUM


organ (-system)

M FSA, 2009; Expert

opinion

81


of inspection

H Expert opinion


will be condemned

L Keenliside, 2006;

Shaw et al., 2009

GREEN OFFAL

(GO) inspection

Probability that macroscopic lesion is present in GO H Expert opinion

GO inspection

Scenario 1



H Expert opinion


will be condemned

N Expert opinion

GO inspection

Scenario 2


palpated




H Expert opinion


will be condemned

N Expert opinion

GO inspection

Scenario 3





will be condemned


Oth

er

Laboratory

testing




Carcase

rectification

after PM






- Assumption


chilling


82

Table 13: Input data, assumptions, likelihood estimates and data sources for the model application to tail bite

in pigs. This hazard is evaluated in relation to its animal welfare aspect (MI = meat inspection, Mod. = module,

PM = post-mortem, LHE = likelihood estimate according to table 1: N = Negligible, VL = Very low, L = Low,

M = Moderate, H = High).


Lair

age

Arrival Animal prevalence 3 % Hunter et al., 1999;

NADIS, 2007;

Expert opinion



- Assumption

Check FCI and

selection of

animal for

routine

slaughter






H Assumption

Lairage - Cross

contamination/

infection

Not applicable to animal welfare hazards N Assumption

Ante-mortem

inspection and

selection of

animals

All tail bitten animals carry a lesion as a tail bite is a

lesion per se. Healed tails are not considered, only

those where lesion is visible and still present.

- Assumption




clinical sign).

H FSA, 2009; Expert

opinion


separated

N FSA, 2009; Expert

opinion

Slau

ghte

r Stunning to

presenting of

carcase to PM


prevalence

- Assumption

Po

st-m

ort

em in

spec

tio

n


present in organ only lesions associated with tail

bite are considered

- Assumption

WHOLE

CARCASE

(EXTERNAL

SURFACES)


organ (-system)

H Expert opinion


of inspection

H Expert opinion


will be condemned

M NADIS, 2007;

Expert opinion

LUNGS


organ (-system)

L Huey et al., 1996;

Expert opinion

83


of inspection

H Expert opinion

If a lesion is visible in a body part /organ in addition

to spine, then total condemnation

- Assumption

Abscesses in lung are only considered if they occur

in combination with abscesses in tail; they are not

counted if abscess is found only in lung

- Assumption


will be condemned

H Author’s opinion

GREEN OFFAL

(GO) inspection

Probability that macroscopic lesion is present in GO

No literature was found that supports presence of

abscesses in green offal. Mostly: carcase incl. tail

and spine, lung, rarely in heart, liver, umbilicus,

head and peritoneum

N Author’s opinion,

supported by Huey

et al., 1996; EFSA,

2007

GO inspection

Scenario 1





will be condemned


GO inspection

Scenario 2


palpated






will be condemned


GO inspection

Scenario 3





will be condemned


Oth

er

Laboratory

testing




Carcase

rectification

after PM






- Assumption


chilling


Hazard is present as long carcase of tail bitten

animal is in chiller

- Assumption

Lesion is present as long carcase of tail bitten

animal is in chiller, which has not be tail-trimmed

- Assumption

84

Table 14: Meat inspection tasks according to Regulation (EC) No 854/2004. (Optional = in the discretion of the meat inspector. "When necessary").

Annex 5 – Meat inspection tasks according to Regulation (EC) No. 854/2004

SHEEP CATTLE PIGS

Young** Old

Obli-

gatory

Opt-

ional

Obli-

gatory

Opt-

ional

Obli-

gatory

Opt-

ional

Obli-

gatory

Opt-

Ional

ANTE-MORTEM V

V

V

V

PO

ST -

MO

RTE

M IN

SPEC

TIO

N

WHOLE CARCASE External surface V

V

V

V

HEAD

Head, mouth, throat

etc. V*

V

V

V

Retropharyngeal LNN

V* I

I

Submaxillary LNN

I

I

Parotid LNN

V*

I

Maseter muscles

I

Tongue

V* P

V + P

V

LUNGS

Parenchyma V+P I V + P

+I*

V + P

+I* V + P+I*

Trachea V I V + I*

V + I*

V+I*

Major bronchi

I*

I*

I*

Mediastinal LNN P I I

I

P

Bronchial LNN P I I

I

P

OESOPHAGUS V I V

V

V

HEART Heart V I V + I

V + I

V + I

Pericardium V

V

V

V

DIAPHRAGM V

V

V

V

LIVER

Parenchyma V + P +

I V + P I

V + P

+ I V+P

Hepatic LNN (=portal) V + P

V + P I V+P

V+P

Pancreatic LNN V

V

V+P

V

GI TRACT

Stomach and intestines V

V

V

V

Mesentery V

V

V

V

Gastric LNN V

V + P I V + P I V + P I

Mesenteric LNN V

V + P I V + P I V + P I

SPLEEN V P V P V P V P

KIDNEYS Parenchyma V I V I V I V I

Renal LNN

I

I

I

I

GENITALS and

assoc. Organs

Uterus V

V

V

Udder V

V (P+I)* V

Supramammary LNN V

V (P+I)* (V+I)***

PLEURA V

V

V

V

PERITONEUM V

V

V

V

UMBILICAL AREA (V+P)** I** V+P I

(V+P)** I**

JOINTS (V+P)** I** V+P I

(V+P)** I**

V: visual inspection, P: palpation, I: incision * not required if organs are not destined for human consumption **only in young animals (Bovines: <6wks old) ***only in sows

research project - final report form - Food Standards Agency

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