Abstract

Studies were carried out in 1990 on the efficacy of sterilisation processes at three rendering plants for dead animals and animal wastes in the Netherlands. Spores of sulfite reducing clostridia were detected in 11.8% of the samples taken directly after autoclaving. C.perfringens was detected in 1.2% of the samples from plant A and in 2.9% of the samples from plant C. At plants A, B and C Salmonella was detected in 0%, 2.2% and 20.0% respectively of samples of final products and in 12.0%, 9.1% and 80.0% respectively of samples of dust taken from the processing halls. In all but one samples of final products the number of Enterobacteriaceae was less than 10 cfu per gram. Higher numbers of Enterobacteriaceae were detected incidentally in dust samples from plants A and B, but frequently in dust samples from plant C. This result suggests that the contamination of final products at plant C was due to poor hygienic conditions.