|Hong, Yoon-ki - Kangwon National University|
|Yoon, Won Byong - Kangwon National University|
Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2015
Publication Date: 9/1/2015
Citation: Hong, Y., Huang, L., Yoon, W. 2015. Mathematical modeling and growth kinetics of Clostridium sporogenes in cooked beef. Food Microbiology. 60:471-477.
Interpretive Summary: Clostridium botulinum is a fatal foodborne pathogen and a serious public health hazard. The spores of this microorganism may grow in processed meats. This study was conducted to evaluate the possibility of using Clostridium sporogenes PA 3679 as a non-pathogenic surrogate for proteolytic Clostridium botulinum. Experiments were performed to determine the growth kinetics of Clostridium sporogenes PA 3679 in cooked beef under various temperature conditions. Mathematical models were developed. The results of this study may assist the food industry and regulatory agencies to evaluate the food safety of cooked meats during cooling.
Technical Abstract: 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 spores of C. sporogenes, 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 for predictive microbiology, was used in data analysis. No growth of C. sporogenes was observed at temperatures below 15 degrees C. Between 20 and 47 degrees C, 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 h0 of 10.46. The specific growth rates and lag times determined from the Huang model were analyzed simultaneously. The nominal minimum growth temperature (T0) estimated from the Huang model was 15.1 degrees C, which was 12.7 degrees C for the Baranyi model. The maximum temperature was 48.0 degrees C. The lag time was more accurately estimated by the Huang model. C. botulinum is a serious public hazard and can potentially grow in cooked meats during cooling. C. sporogenes can be a potential surrogate in food to evaluate its growth. The kinetic models developed in this study may provide a tool to examine the growth of C. botulinum in cooked meats during cooling.