Microbiological contamination of cattle carcasses at different stages of slaughter in two abattoirs

Cattle carcasses from two abattoirs were examined at selected stages of slaughter (skinning, evisceration, trimming, washing, blast chilling) for aerobic colony counts (ACC) and Enterobacteriaceae. At each stage and abattoir, 50 carcasses were sampled by swabbing at the neck, brisket, flank and rump. After skinning, average ACC on carcasses was 1.5logCFUcm(-2) and Enterobacteriaceae frequencies at sites were ≤6%. From skinned to washed carcasses, certain abattoir- and site-specific changes occurred. Blasting clearly reduced ACC and Enterobacteriaceae results on carcasses from abattoir B, but reductions were limited or lacking in abattoir A. In addition, 100 hides and corresponding chilled carcasses were examined. On hides, average ACC was 5.6logCFUcm(-2) and Enterobacteriaceae frequencies at sites ranged from 74 to 96%. Average carcass-hide ratios of the two abattoirs were comparable for ACC (0.0182-0.0202%) but differed for Enterobacteriaceae counts (abattoir A: 0.4627%; abattoir B: 0.0941%). Such ratios allow comparing process performance between abattoirs in the daily practice.