Survival of bacteria in carcasses

Abstract

Bacteria injected into the bloodstream of guinea pigs shortly before death decreased in number in carcass tissues for about 1 h after death. If initial bacterial numbers were sufficiently low, all bacteria were eliminated, and carcass tissues were sterile 24 h after death. Carcass tissue sterility was maintained with an initial density of Clostridium perfringens or Salmonella typhimurium of 20 cells per gram or with an initial density of the other species examined of several hundred cells per gram. With larger numbers of strict and facultative anaerobes, growth commenced after 3 h in carcasses incubated at 30°C. Spores of C. perfringens were killed over the same period as vegetative cells, but growth did not commence until 8 h after death. Bactericidal activity in carcass tissues must therefore be taken into account in evaluating the significance of reports of deep tissue contamination of carcasses from meat animals.