Comparison of post-mortem inspection findings of outdoor and indoor fattening pigs

Last updated:
5 April 2010
The current system of post-mortem inspection using the typical macroscopic inspection techniques is ineffective in identifying the most common foodborne illness risks, e.g. Salmonella and Campylobacter. Therefore, there is a need to adopt a more appropriate, risk-based approach to meat inspection.
Study duration: April 2010 to January 2011
Project code: MC1002
Contractor: Veterinary Laboratories Agency

Background

(FS245009) EC Regulation 854/2004 allows for fattening pigs, housed under controlled conditions since weaning, to undergo only visual inspection, rather than the mandatory palpation of major organs and incisions in the heart and lymph nodes, which applies to outdoor pigs. This study tested the assumption that outdoor pigs require invasive inspection to guarantee adequate consumer protection levels. A qualitative veterinary risk assessment was used to evaluate the changes in human/animal risk due to transferring from traditional to visual inspection. Assuming that visual inspection of indoor pigs is an acceptable risk, a risk assessment was produced that estimated the increased risk, if any, posed by outdoor pigs compared with indoor pigs. Based on this assessment of the potential hazards to public health, animal health and welfare for visual inspection of outdoor pigs, it is possible to determine whether these hazards constitute an acceptable risk.

Research Approach

Conditions that are prevalent in outdoor pigs rather than indoor pigs, and which are likely to be missed by visual inspection but detected using traditional inspection methods were identified and termed as ‘critical conditions’. The prevalence of these particular conditions was assessed by analysing datasets from the FSA Operations Group, British Pig Health Scheme, Wholesome Pigs Scotland and Food Chain Information from abattoirs.
To assess any increased human/animal exposure to critical conditions because of visual inspection of outdoor pigs, each condition was evaluated so as to discover the likelihood of not detecting them in outdoor pigs compared to indoor pigs.
Individual risk estimates for each critical condition and each risk type (public health, animal health and welfare) were produced.
The results showed where increased risk lies in removing palpation and incision from post-mortem inspection of outdoor pigs, and also established any possible benefits.

Results

The current system of post-mortem inspection using the typical macroscopic inspection techniques is ineffective in identifying the most common foodborne illness risks, e.g. Salmonella and Campylobacter. Therefore, there is a need to adopt a more appropriate, risk-based approach to meat inspection. One specific example of modifying traditional inspection techniques to represent a more cost-effective approach to meat inspection is the allowance in EC Regulation 854/2004 for only visual inspection of pigs that have been reared under controlled housing conditions since weaning. However, the definition of controlled housing excludes outdoor pig production from visual-only meat inspection. We have therefore conducted a qualitative risk assessment to assess the comparative risks to public and animal health from allowing visual-only inspection of both indoor and outdoor pigs.

In order for visual-only inspection to be of higher risk than traditional meat inspection, the sensitivity of detection of a condition must significantly decrease for visual-only inspection. In addition, in order for outdoor pigs to pose a greater risk than indoor pigs, then the condition must be more prevalent in the former than the latter. From a large number of diseases/conditions originally identified as worthy of investigation, only two (porcine tuberculosis (pTB, primarily M. bovis/M. avium) and endocarditis) were considered to be of public or animal health risk and would be less likely to be spotted through visual-only inspection. Despite higher rates of pTB in outdoor pigs than indoor pigs, the relatively small number of additional heads/carcasses that would be missed by including outdoor pigs in visual-only meat inspection (compared to traditional meat inspection) would pose a negligible risk to public health and a negligible-very low risk to animal health/welfare. The prevalence of endocarditis was higher in indoor pigs than outdoor pigs; hence the risk to public and animal health, regardless of inspection system, should be lower for outdoor pigs than indoor pigs. The risk to both public and animal health by transferring to a visual-only inspection method was assessed as negligible for all pigs, and hence was also assessed as negligible should outdoor pigs be included in the regulations for visual-only meat inspection.

Published Papers

  1. Hill A., Brouwer A., Donaldson N., Lambton S., Buncic S. & Griffiths I., A risk and benefit assessment for visual-only meat inspection of indoor and outdoor pigs in the United Kingdom, Food Control (2012), doi: 10.1016/j.foodcont.2012.04.031.