Visual cleanliness scores of cattle at slaughter and microbial loads on the hides and the carcases

In two abattoirs, visual cleanliness of 100 cattle was assessed before slaughter (on a scale of 1 to 4). From each animal, two sponge swabs (approximately 2000 cm(2) area, each) were taken: (a) from hide, immediately after sticking, and (b) from final carcase, but before chilling. In each swab sample, total viable count (TVC), Enterobacteriaceae count (EC) and the presence of Escherichia coli O157 were determined. The mean TVC/EC status of hides and final carcases differed significantly only between very dirty cattle (category 4) and all other less dirty or clean cattle (categories 1, 2 and 3), but not between the less dirty and clean cattle (between categories 1, 2 and 3). However, no clear relationship between the visual cleanliness of the hide and the occurrence of E coli O157 on hide or dressed carcases was observed. The study indicated the possibility that visual categorisation of cattle into only two main categories - one containing very dirty animals (category 4 in this work, corresponding to categories 4+5 in The UK Food Standards Agency system) and another containing all the other less dirty or clean animals (categories 1+2+3) - could be sufficient in practice.