Mathematical modeling and growth kinetics of Clostridium sporogenes in cooked beef

초록

Clostridium sporogenes PA 3679 is a common surrogate for proteolytic Clostridium botulinum for thermal process development and validation. However, little information is available concerning the growth kinetics of C. sporogenes in food. Therefore, the objective of this study was to investigate the growth kinetics of C. sporogenes in cooked beef under different temperature conditions. Ground beef samples, inoculated with C. sporogenes spores, were incubated at temperatures between 8 and 47 degrees C to examine the growth of this microorganism. Two primary models (Huang and Baranyi models) were used to analyze the growth data. The Ratkowsky square-root model was used as the secondary model to evaluate the effect of temperature on bacterial growth rate and lag time. The USDA IPMP 2013, a free data analysis tool for predictive microbiology, was used in data analysis. No growth of C. sporogenes was observed at temperatures below 15 degrees C for up to 25 days. At temperatures between 20 and 47 degrees C, C. sporogenes grew in cooked beef. The growth curves could be analyzed by both Huang and Baranyi models. The root mean squared error (RMSE) was 0.375 for the Huang model, and 0.441 for the Baranyi model with a global 110 of 10.46. The nominal minimum growth temperature (T-0) estimated from the Huang model was 15.5 degrees C, which was 12.7 degrees C for the Baranyi model. The maximum growth temperature was 48.0 and 48.3 degrees C for the Baranyi and Huang models, respectively. The lag times and specific growth rates of C. sporogenes observed in this study were reasonably close to the data reported in the literature for C. botulinum under comparable conditions, suggesting that C. sporogenes may be used as a potential surrogate for evaluating the growth of C. botulinum in cooked meats during cooling. However, a direct comparison of growth kinetics between the two microorganisms is needed to confirm the suitability of C. sporogenes as a surrogate of C. botulinum. Published by Elsevier Ltd.

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