Thermal inactivation of Bacillus cereus and Clostridium perfringens vegetative cells and spores in pork luncheon roll

The aim of this study was to design a thermal treatment(s) for pork luncheon roll, which would destroy Bacillus cereus and Clostridium perfringens vegetative cells and spores. B. cereus and C. perfringens vegetative and spore cocktails were used to inoculate luncheon meat. Samples were subjected to different temperatures and removal times. The decimal-reduction times (D-values) were calculated by linear regression analysis (D=−1/slope of a plot of log surviving cells versus time). The log10 of the resulting D-values were plotted against their corresponding temperatures to calculate (−1/slope of the curve) the thermal resistance (z-values) of each cocktail. The D-values for vegetative cells ranged from 1 min (60 °C) to 33.2 min (50 °C) for B. cereus and from 0.9 min (65 °C) to 16.3 min (55 °C) for C. perfringens. The D-values for B. cereus spores ranged from 2.0 min (95 °C) to 32.1 min (85 °C) and from 2.2 min (100 °C) to 34.2 min (90 °C) for C. perfringens. The z-values were calculated to be 6.6 and 8.5 °C for B. cereus vegetative and spores, respectively, and 7.8 and 8.4 °C for C. perfringens vegetative cells and spores, respectively.