Effects of fleece soiling and skinning method on the microbiology of sheep carcases.

The fleece of sheep becomes soiled primarily on the abdomen and on the legs. A five-category scoring scale for soiling of the fleece was defined, with score 1 being clean and dry and score 5 being wet and heavily soiled with faecal material. Twenty sheep with each fleece score were slaughtered and dressed on a commercial 'inverted' slaughter line. Swab samples were taken from the shoulder and the abdomen of the carcases immediately after skinning, and total viable counts and the numbers of Enterobacteriaceae were determined. The condition of the fleece significantly affected the microbial load on these parts of the dressed carcase, with the carcases derived from sheep with increasingly dirty fleeces carrying up to 1000 times more microorganisms, and a higher proportion of the carcases being contaminated with Enterobacteriaceae. Modifications to the dressing procedure were made to try to reduce carcase contamination at the shoulder. The application of bulldog clips to prevent direct contact between the fleece and the underlying muscles resulted in higher counts on carcases with a fleece score of 3, probably owing to contamination from the hands of the slaughterman and the problems with ensuring that the clips were in place before contamination had occurred. Delaying the skinning of the shoulder until later in the pelt removal process achieved worthwhile reductions in the contamination of the shoulder of carcases with a fleece score of 4, although the total viable counts were still higher than carcases with a score of 3.