Use of fluorescence imaging as a hygiene indicator for beef and lamb carcasses in UK slaughterhouses

Faeces from cattle and lamb contain products of digestion of chlorophyll that fluoresce. A hand-held fluorescence imager was used to detect faecal contamination on carcasses in beef and lamb slaughterhouses. On beef carcasses, almost all contaminants were found along the legs and the ventral cut line with most (p < 0.005) being faecal (62%); 36% were hairs, and 2% were other contaminants, such as rail grease. The average number of incidents of contamination per beef carcass was 23. There were significant differences in contamination levels at different slaughterhouses (p < 0.001). Carcasses from young cattle showed lower occurrences of contamination than those from older animals (p < 0.001). The average number of incidents of contamination on lambs was 25 per carcass. Most of these contaminants were found on the hind legs, breast and sides of the neck. It was concluded that fluorescence imaging could be used as part of an in-plant monitoring system for carcass hygiene.