Survival of Clostridium perfringens , Staphylococcus aureus, Listeria monocytogenes and Salmonella enterica in alternatively cured ham during cooking and process deviations

Boneless hams were prepared with four different brines and inoculated on the surface and at a depth of 1 cm with multiple strains of Clostridium perfringens, Staphylococcus aureus, Listeria monocytogenes and Salmonella enterica. Hams were processed with a standard, low relative humidity or interrupted process cycle to an end point temperature of 70 °C. Microbiological populations were determined at the beginning, mid-point and end of the cycles. The change in population was calculated for each bacterium at each time point, by comparing the population to the initial inoculated population. There was no difference in the reductions in bacterial populations for all of the inoculated bacteria attributable to brine type. There were significant reductions in the populations of Staphylococcus aureus, Listeria monocytogenes and Salmonella enterica for both the surface and interior samples which were attributable to the end point temperature. Population reductions for Clostridium perfringens were approximately 1.8 log 10 for both the surface and internal samples, and the population reductions for the surface samples were greatest with the interrupted cycle. The low Rh cycle resulted in the least reductions for the surface samples while the greatest population reductions for the surface samples were observed with the interrupted cycle.