MODELING THE THERMAL RESISTANCE OF CLOSTRIDIUM SPOROGENES SPORES UNDER DIFFERENT TEMPERATURE, pH AND NACl CONCENTRATIONS

The objective of this study was to examine the effects of temperature (101–121C), pH value (5.5–6.5) and concentration of sodium chloride (2–6%) on the heat resistance of Clostridium sporogenes spores under laboratory conditions. The inactivation curves of spore reduction from 1010 to 105 cfu/mL were fitted by Weibull frequency distribution model, and the primary fitting equations were obtained with R2 > 0.90. Moreover, the inactivation parameters δ and p of Weibull functions were modeled using a quadratic polynomial equation of response surface model (RSM). Mathematical evaluation demonstrated that the standard error of prediction (%SEP) obtained by RSM was 11.826 and 6.735% for model establishing δ and p, respectively, and 1.390 and 9.907% for model validation, respectively. The root mean square error was less than 0.05 for δ and p. Both the bias factor and accuracy factor were within acceptable range for model establishing and validation. Therefore, RSM provides a useful and accurate method of fitting the effects of experimental conditions on the thermal resistance of C. sporogenes spores, and could be referenced to ensure food safety with respect to C. sporogenes spores control. PRACTICAL APPLICATIONS Weibull frequency distribution model could be used for establishing nonlinear heat resistance models of Clostridium sporogenes spores under laboratory media conditions. The interacting effects of temperature, pH and NaCl concentration might be applied together for inactivating C. sporogenes spores growth in the food, and response surface model could be referenced to ensure food safety with respect to C. sporogenes spores control. Food producers would depend on these models for the decision‐making of food safety after established models are validated under real food environment.