PATHOGENIC MICROORGANISMS IN SLAUGHTERHOUSE SLUDGE - A SURVEY

During slaughtering of animals and subsequent meat processing the proc ess water used becomes polluted with organic matter of animal origin ( i.e. protein and fat). This organic sludge is, in principle, a product suitable for animal feeding. To investigate the microbiological conta mination level of sludge, raw sludge was collected at pig (n = 8) and poultry (n = 5) slaughterhouses. Both flocculated and aerobically acti vated sludge was monitored. Slaughterhouse sludge was heavily contamin ated with Enterobacteriaceae (6.3-10.0 in log(10) N/gram dry matter) a nd enterococci (4.6-7.9). Clostridia were present in sludge at a level of 3.1-5.8 (in log(10) N/g DM). Salmonella was present in the sludge from all slaughterhouses examined. Yersinia enterocolitica serotypes O :3 and O:9 were found in sludge from seven out of thirteen slaughterho uses. The prevalence of Campylobacter jejuni/coli was higher in floccu lated poultry sludge than in both flocculated pig sludge and aerobical ly activated pig sludge. Obviously, decontamination of the sludge is m andatory when it is to be applied as a feed constituent, to prevent ba cterial cycles from occurring in livestock, as well as the spread of h uman pathogenic zoonoses like campylobacter, salmonella and yersinia, to minimize loss of protein quality by the microbial breakdown of amin o acids and the formation of possible toxic metabolites in sludge duri ng storage.