Pathogenic micro-organisms in slaughterhouse sludge--a survey.

During slaughtering of animals and subsequent meat processing the process 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 contamination level of sludge, raw sludge was collected at pig (n = 8) and poultry (n = 5) slaughterhouses. Both flocculated and aerobically activated sludge was monitored. Slaughterhouse sludge was heavily contaminated with Enterobacteriaceae (6.3-10.0 in log10 N/gram dry matter) and enterococci (4.6-7.9). Clostridia were present in sludge at a level of 3.1-5.8 (in log10 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 slaughterhouses. The prevalence of Campylobacter jejuni/coli was higher in flocculated poultry sludge than in both flocculated pig sludge and aerobically activated pig sludge. Obviously, decontamination of the sludge is mandatory when it is to be applied as a feed constituent, to prevent bacterial cycles from occurring in livestock, as well as the spread of human pathogenic zoonoses like campylobacter, salmonella and yersinia, to minimize loss of protein quality by the microbial breakdown of amino acids and the formation of possible toxic metabolites in sludge during storage.

Critical points in meat production lines regarding the introduction of Listeria monocytogenes.

In order to elucidate critical points concerning Listeria monocytogenes during bovine and porcine slaughter, cutting and processing, 843 samples were obtained from carcasses, primal cuts, products at retail and from environmental surfaces. Only 2-7% of the carcasses and 0-10% of the environmental samples in the 'clean' part of the pork slaughterline were found to be positive for L. monocytogenes. The incidence of L. monocytogenes was increased after chilling and cutting. In the cutting room 11-36% of the primal cuts and 71-100% of the environmental samples were found positive for L. monocytogenes. Our findings indicate that contamination of pork meat with L. monocytogenes originates from the processing environment of the chilling or cutting room. The incidence of L. monocytogenes in the bovine cutting and meat processing line (0-60%) was lower than in the porcine cutting and meat processing line (11-100%).