Assessing Salmonella typhimurium persistence in poultry carcasses under multiple thermal conditions consistent with composting and wet rendering

Mitigation of Salmonella associated with poultry carcasses is primarily accomplished by rendering or carcass composting. While rendering temperatures and pressures are well established for pathogen inactivation in poultry carcasses, parameters controlling composting processes are less defined in part because multiple conditions and procedures are utilized. Consequently, limited knowledge exists describing the impacts of composting with varying temperature and mixing protocols with respect to the inactivation of Salmonella in poultry carcasses. To improve the existing knowledge of Salmonella survival in poultry carcasses, inactivation of Salmonella enterica serovar Typhimurium (ST) LT2 was investigated. The impacts of various composting temperatures (55, 62.5 degrees C) and low-rendering (i.e., pasteurization) temperatures (70, 78 degrees C) on Salmonella inactivation were tested in a bench-top setting using a ground carcass slurry and whole birds under mixed and non-mixed conditions. Results showed that the ground carcass slurry and the whole carcass exposed to temperatures consistent with composting had no detectable Salmonella after 110 h with a level of detection of one CFU/mL of ground carcass slurry and one CFU/g of whole carcasses, respectively. In addition, grinding of carcasses as opposed to whole carcasses was more predictable with respect to Salmonella heat inactivation. Furthermore, results showed that constant mixing decreased the overall time required to eliminate Salmonella under composting and low-rendering temperatures.