Meat safety consequences of implementing visual postmortem meat inspection procedures in Danish slaughter pigs

Abstract

The consequences of a change from a traditional meat inspection procedure, including manual handling, palpation and incision, to an entirely visual postmortem meat inspection procedure in Danish slaughter pigs were assessed by a comparative study of the two methods in 183,383 slaughter pigs. Out of 58 lesion codes (selected with a prevalence > or = 5.5 x 10(-5)), 26 (45 per cent) were assessed either as merely aesthetic or as the healed stage of an earlier lesion and nine (15 per cent) as active, but local processes, occurring only in non-edible tissue. Five lesion codes (9 per cent) were assessed as active, non-abscessal processes occurring in edible tissue, caused by swine-specific pathogens and 10 (17 per cent) were abscessal or pyaemic lesions occurring in edible tissue. Seven lesion codes (12 per cent) may be associated with consumer health hazards (two frequently and five rarely), and one with occupational health hazards. It was estimated that per 1000 carcases, an additional 2.5 with abscessal or pyaemic lesions (in edible tissue) containing Staphylococcus aureus, 4 x 10(-4) containing ochratoxin, 0.2 with arthritis due to Erysipelothrix rhusiopathiae, 0.1 with caseous lymphadenitis, 0.7 faecally contaminated with Salmonella species, and 3.4 faecally contaminated with Yersinia enterocolitica would remain undetected as a result of changing from the traditional to the visual inspection procedure. Two valuable reasons for implementing a visual control system are the potential for decreased cross-contamination (no handling, cutting and incision) and reduced inspection costs. The resources released as a result may be reallocated to hygiene and surveillance programmes.

The occurrence and epidemiology of Salmonella in European pig slaughterhouses

“…Unlike some of the classical zoonotic diseases, e.g. tuberculosis, salmonellosis cannot be detected by the traditional meat inspection [16]. Salmonella bacteria are primarily located in the gastro-intestinal tract from the oral cavity to the rectum of the subclinically infected pigs.…”

Comparison of two different meat inspection techniques

“…Compared with the results of other research groups (2,5,7,13,15), the prevalence of the lesions was quite high, which may be explained by the structure of husbandry, different facilities, or different climates in the different countries. Moreover, the data may not be totally comparable, because the recording of lesions followed to some extent different definitions.…”

“…The prevalence was in all cases about 1% (Danish data unpublished), so results are quite comparable, with the exception of abscesses in lungs monitored by Harbers (5), where a higher prevalence was observed (2 and 4%). Slightly different definitions of necrosis of the tail were used in the Danish and Dutch studies and in our study: inflammation of the tail in the Netherlands (5), tailbite/abscess in Denmark (13), and tail biting as well as abscesses of the spine in our study. In all cases the prevalence was below 1% (Danish data unpublished).…”

“…Lesions such as abscesses or necroses were monitored in a different way. Only abscesses in the lungs were monitored in the Dutch (7) and the Italian (2) studies, whereas in the Danish study (13) lesions in several locations were recorded, as they were in this study. The prevalence was in all cases about 1% (Danish data unpublished), so results are quite comparable, with the exception of abscesses in lungs monitored by Harbers (5), where a higher prevalence was observed (2 and 4%).…”

“…Hathaway et al (11) compared the results of three macroscopic meat inspection techniques (observation, palpation, and cutting) used to inspect the spleen of lambs in New Zealand. In Denmark 'traditional' and 'visual' meat inspection systems, were compared by Mousing et al (13) and Willeberg et al using data from 183, 383 slaughter pigs (14,15). In the Netherlands the group of Harbers et al investigated the interrelationship between data from the farm of origin and the results of meat inspection (5,6,8,10) and the technique of inspection (5,7,9).…”