Relevance of carcass palpation in lambs to protecting public health

The Importance of the Slaughterhouse in Surveilling Animal and Public Health: A Systematic Review

From the point of public health, the objective of the slaughterhouse is to guarantee the safety of meat in which meat inspection represent an essential tool to control animal diseases and guarantee the public health. The slaughterhouse can be used as surveillance center for livestock diseases. However, other aspects related with animal and human health, such as epidemiology and disease control in primary production, control of animal welfare on the farm, surveillance of zoonotic agents responsible for food poisoning, as well as surveillance and control of antimicrobial resistance, can be monitored. These controls should not be seen as a last defensive barrier but rather as a complement to the controls carried out on the farm. Regarding the control of diseases in livestock, scientific research is scarce and outdated, not taking advantage of the potential for disease control. Animal welfare in primary production and during transport can be monitored throughout ante-mortem and post-mortem inspection at the slaughterhouse, providing valuable individual data on animal welfare. Surveillance and research regarding antimicrobial resistance (AMR) at slaughterhouses is scarce, mainly in cattle, sheep, and goats. However, most of the zoonotic pathogens are sensitive to the antibiotics studied. Moreover, the prevalence at the slaughterhouse of zoonotic and foodborne agents seems to be low, but a lack of harmonization in terms of control and communication may lead to underestimate its real prevalence.

Comparison of postmortem inspection procedures for detecting caseous lymphadenitis of Australian sheep and goats

Alternative postmortem inspection procedures for the detection of gross abnormalities due to Caseous Lymphadenitis (CLA) of sheep and goats were compared quantitatively against the current Australian Standard (AS4696). Studies on sheep and goats in Australia during 2016 addressed data gaps regarding current prevalence, combinations of multiple lesions within affected carcases and sensitivity of inspection procedures enabling a comparison of alternative with current procedures. Using these contemporary inspection data from 54 915 sheep and 48 577 goats a desktop study estimated the effect of implementing alternative procedures of reduced palpation from eleven carcase sites to the four sites most commonly affected. Under current procedures it was estimated that 86 sheep and 34 goat carcases with CLA lesions are missed per 10,000 carcases. Under alternative procedures it is estimated that an additional 48.4 sheep and 10.5 goat carcases with CLA lesions would be missed per 10 000 carcases. Of these, 38.2 sheep and 5.6 goat per 10 000 carcases would contain CLA only in routinely discarded, non-edible tissue sites. Hence, only an additional 10.2 sheep and 4.9 goat carcases per 10 000 inspected, with CLA in edible tissue sites are estimated to be missed. These alternative procedures have now been officially implemented in the Australian domestic standard.

Evaluation of Carcass Hygiene in Sheep Subjected to Gas De-Pelting With Different Skinning Procedures

The aim of the study was to evaluate the hygienic status of sheep carcasses skinned with two different procedures, the pulling down and Y cut methods, with and without the use of compressed filtered air inflation. Five sheep carcasses per day for each of the four skinning methods considered were sampled on ten different slaughtering days using wet and dry swab techniques at a local abattoir specialised in ovine slaughtering. A pool of four different sampling sites (brisket, shoulder, thorax and rump) was considered for each animal. Furthermore, ten animals were also randomly selected on different slaughtering days for each of the four skinning techniques and the four sampling sites were separately swabbed and analysed in each animal. The total viable count (TVC) and Enterobacte riaceae count were performed and the presence of Salmonella spp. was also tested. The daily average mean value of each parameter was in compliance with limits set by Regulation (EC) 1441/2007, falling into satisfactory or acceptable category for Enterobacteriaceae and within the acceptable level range for TVC for both the methods used with and without air de-pelting. For both TVC and Enterobacteriaceae count, no statistically significant differences (P>0.05) were recorded between samples obtained from carcasses skinned with and without air inflation for either of the skinning methods used and any of the sites sampled. No Salmonella spp. were detected in any of the tested samples. Nonetheless, no improvement in the carcass hygiene was detected either and, for this reason, other aspects should be taken into consideration when considering adopting the gas de-pelting method.

EFSA Panel on Biological Hazards (BIOHAZ). Scientific Opinion on the public health hazards to be covered by inspection of meat from sheep and goats

A risk ranking process identified Toxoplasma gondii and pathogenic verocytotoxin-producing Escherichia coli (VTEC) as the most relevant biological hazards for meat inspection of sheep and goats. As these are not detected by traditional meat inspection, a meat safety assurance system using risk-based interventions was proposed. Further studies are required on T. gondii and pathogenic VTEC. If new information confirms these hazards as a high risk to public health from meat from sheep or goats, setting targets at carcass level should be considered. Other elements of the system are risk-categorisation of flocks/herds based on improved Food Chain Information (FCI), classification of abattoirs according to their capability to reduce faecal contamination, and use of improved process hygiene criteria. It is proposed to omit palpation and incision from post-mortem inspection in animals subjected to routine slaughter. For chemical hazards, dioxins and dioxin-like polychlorinated biphenyls were ranked as being of high potential concern. Monitoring programmes for chemical hazards should be more flexible and based on the risk of occurrence, taking into account FCI, which should be expanded to reflect the extensive production systems used, and the ranking of chemical substances, which should be regularly updated and include new hazards. Control programmes across the food chain, national residue control plans, feed control and monitoring of environmental contaminants should be better integrated. Meat inspection is a valuable tool for surveillance and monitoring of animal health and welfare conditions. Omission of palpation and incision would reduce detection effectiveness for tuberculosis and fasciolosis at animal level. Surveillance of tuberculosis at the slaughterhouse in small ruminants should be improved and encouraged, as this is in practice the only surveillance system available. Extended use of FCI could compensate for some, but not all, the information on animal health and welfare lost if only visual post-mortem inspection is applied.

Experimental comparison of excision and swabbing microbiological sampling methods for carcasses

Bovine sides, ovine carcasses, and porcine carcasses were individually inoculated by dipping in various suspensions of a marker organism (Escherichia coli K-12 or Pseudomonas fluorescens), alone or in combination with two meat-derived bacterial strains, and were sampled by two standard methods: cotton wet-dry swabbing and excision. The samples were examined for bacterial counts on plate count agar (PCA plate counts) and on violet red brilliant green agar (VRBGA plate counts) by standard International Organization for Standardization methods. Average bacterial recoveries by swabbing, expressed as a percentage of the appropriate recoveries achieved by excision, varied widely (2 to 100%). Several factors that potentially contributed to relatively low and highly variable bacterial recoveries obtained by swabbing were investigated in separate experiments. Neither the difference in size of the swabbed area (10, 50, or 100 cm2 on beef carcasses) nor the difference in time of swabbing (20 or 60 min after inoculation of pig carcasses) had a significant effect on the swabbing recoveries of the marker organism used. In an experiment with swabs preinoculated with the marker organism and then used for carcass swabbing, on average, 12% of total bacterial load was transferred inversely (i.e., from the swab to the carcass during the standard swabbing procedure). In another experiment, on average, 14% of total bacterial load was not released from the swab into the diluent during standard swab homogenization. Use of custom-made swabs with abrasive butts, around which metal pieces of pan scourers were wound, markedly increased PCA plate count recoveries from noninoculated lamb carcasses at commercial abattoirs compared with cotton swabs. In spite of the observed inferiority of the cotton wet-dry swabbing method compared with the excision method for bacterial recovery, the former is clearly preferred by the meat industry because it does not damage the carcass. Therefore, further large-scale evaluation of the two carcass sampling methods has been undertaken under commercial conditions and reported separately.