The relationship between hide cleanliness and bacterial numbers on beef carcasses at a commercial abattoir.

Cattle were visually inspected in the lairage of a commercial abattoir and assigned to a category ranging from 1 (very clean) to 5 (very dirty) depending on the observed cleanliness of the hide. Animals from categories 2, 3 and 5 were slaughtered and total viable counts (TVCs) enumerated at five sites (hock, brisket, cranial back, bung and inside round) on the subsequent carcasses. The TVCs at the hock were significantly higher on category 5 than on category 2 carcasses (P < 0.05). Similarly, TVCs at the brisket were significantly higher on categories 3 and 5 than on category 2 carcasses (P < 0.05). There were no differences in counts among the categories at any of the other sites. The TVCs averaged over the five carcass sites were higher for category 5 than for category 2 carcasses (P < 0.05). The TVCs at the brisket were significantly higher than all other sites (P < 0.01). In general, carcasses from category 2 animals slaughtered in a batch with dirtier animals (categories 3 and 5) did not have higher TVCs than carcasses of category 2 animals slaughtered at the beginning of the day in the absence of dirtier animals. The introduction of improved hygienic practices during the dehiding of category 4 animals resulted in reduced TVCs at the brisket (P < 0.001).