Meat inspection plays an important role in the surveillance of many animal diseases (bovine tuberculosis being a very good example) and the verification of compliance with animal welfare standards. A few years back, the European Food Safety Authority brought together experts to agree and publish six scientific opinions on public hazards linked to meat inspection.
The Codex Alimentarius in its Code of Hygienic Practice for Meat (CAC/RCP 58-2005) describes ante-mortem meat inspection as
“any procedure or test conducted by a competent person on live animals for the purpose of judgement of safety and suitability and disposition”
This blog post today will explain how information collected during ante-mortem meat inspection is/can be used to support animal health and food safety in the EU.
In bovine animals, ante-mortem meat inspection is carried out at the time of arrival and in the lairage pens (pens where animals rest before slaughter). The inspector first checks the animal identification for traceability and uses the visual inspection of the animal to take decisions relative to :
- whether animals can progress to slaughter normally or should be separated from the normal slaughter. For example, cattle with diarrhoea or with extensive signs of faecal contamination may be associated with an increased risk of microbial cross-contamination during slaughter and should be slaughtered separately.
- which animals must be removed from the food chain. For example, an animal that has died during transport.
- which animals should go through a more detailed post-mortem examination. For example, based on external observations of the animal’s general health status and/or the food chain information given by the farmer (e.g. treatment history).
An important outcome of the ante-mortem meat inspection is the provision of feedback to the producers on problems detected. Most commonly, the problems detected will be relevant to animal welfare (e.g. lameness in dairy cows) and not directly related to public health.
As can also be the case for bovine animals, the high number of pigs arriving together for slaughter may not allow for the clinical examination of individuals and groups may be observed instead for clinical signs of disease. The foot and mouth disease epidemic in the UK in 2001 was first identified following suspicion of lameness in sows during ante mortem meat inspection.The visual cleanliness of animals for microbial status of carcasses is less relevant for pigs whose carcasses are subjected to scalding.
Animals (or groups) exhibiting signs of a recent medical treatment (e.g presence of injection sites or alterations of the reproductive organs) may be noted subjected to sampling for the presence of residues and contaminants. Experts have also recommended that palpation and incisions should be omitted during post-mortem inspection of pigs from routine slaughter that had no abnormalities found at ante-mortem inspection to limit Salmonella and Yersinia enterocolitica cross-contamination, thereby reducing related pork safety risks.
Measures of injuries (e.g. tail biting) detected during ante-mortem meat inspection also constitute on-farm welfare-outcome indicators that could be used to enforce control measures or manage product quality programmes. While experts also highlights the potential value of on-farm ante-mortem inspection for pigs, it should supplement, not replace abattoir-based ante-mortem inspection which alone can detect welfare problems related to transport and lairage (e.g bruising, bone breakage).
According to Regulation (EC) No 854/2004, ante-mortem meat inspection of poultry can be performed either at the slaughterhouse or at the farm. In practice, the former is more common. Ante-mortem examination is carried out only on groups of birds in a sample of stacked transport crates (like the one in the picture above). The observation of individual birds in the crates is difficult, and often, only the most accessible crates will be checked. For poultry, all food chain information is provided at flock/farm level, and not at individual level.
If repeatedly high condemnation rates have been observed in previous flocks (e.g. foot pad dermatitis), ante-mortem meat inspection on farm may be preferred. When conducted on farm, the examination may give a better overview of the birds than when it is conducted at the slaughterhouse, although such practice can also can increase the risk of the inspector spreading infection within and among farms. Inspection on farm will also miss out on the detection of welfare issues during transport which can lead to bird mortality prior to slaughter and birds with major fractures.
What ante-mortem meat inspection does
- Visual ante-mortem meat inspection is a rapid and inexpensive way to detect (albeit with moderate sensitivity) diseases and welfare conditions with obvious clinical signs. Abnormalities may be detected visually ante-mortem without a definitive diagnosis in the absence of a follow-up (e.g. samples sent to laboratories for testing), although ante-mortem inspection results can be used to inform sampling procedures during post-mortem inspection.
- Ante-mortem inspection upon arrival at the slaughterhouse is an important procedure that helps to enforce acceptable standards for animal transport and handling, thereby reducing the risks (e.g. increased excretion rate and spread of Salmonella) associated with unhygienic and stressful animal management.
What it cannot do
- High-priority meat-borne biological hazards (e.g. E. coli, Salmonella, Taenia saginata) can often not be detected by macroscopic inspection. Animals not showing any externally visible abnormalities at ante- mortem examination may suffer from sub-clinical diseases and asymptomatically carry or shed pathogens of public health relevance.
- It cannot detect the presence of chemical hazards (e.g. residues of veterinary drugs and chemical contaminants).