Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 9/12/2007
Publication Date: 9/16/2007
Citation: Juneja, V.K., Marks, H.M., Huang, L., Thippareddi, H. 2007. Predictive model for growth of Clostridium perfringens at temperatures applicable to cooling of cooked uncured beef and chicken. Meeting Abstract. PA7. Interpretive Summary:
Technical Abstract: The objective of this investigation was to develop and validate a model for predicting the relative growth of Clostridium perfringens from spore inocula in uncured chicken and beef meat during cooling. Isothermal growth curves of C. perfringens at various temperatures from 10-48.9C were evaluated, and from which secondary models for the isothermal growth kinetics were derived. The estimated theoretical minimum and maximum growth temperatures of C. perfringens were about 10 and 53C, respectively. In a cooling study with temperature declining linearly from 54.4C to 27C in 1.5 h, the standard model predicted a relative growth of 1.1 – 1.2 log, while the observed results ranged from about 0.4 to 0.9 log. For the same temperature decline in 3 h, the predicted relative growth was 3.6 log and the observed relative growth was 2.4 - 3.0 log. When the cooling scenarios were extended to lower temperatures, the prediction accuracy was improved. For a cooling scenario of 54.4C to 27C in 1.5 h and 27C to 4 C in 12.5 h, the average predicted and observed relative growths were 3.2 – 3.3 log and 2.4 – 2.9 log, respectively. When cooling (27 to 4C) was extended to 15 h, the average predicted and observed relative growth were 3.6 – 3.7 and 3.4 – 3.7 log, respectively. For the latter cooling scenario, the C. perfringens population was > 6 log, but still less than stationary levels (7 - 8 log). By incorporating “memory,” assuming that the instantaneous cell-state transition rates at a given time are actually functions of the determined (isothermally) instantaneous rates at times equal to or before the given time, the predicted values can be improved to within ± 0.5 log10 of the mean of the observed values for the cooling scenarios. The kinetic growth parameters obtained from this study can be used in evaluating the growth of C. perfringens from spore populations during dynamic conditions such as those encountered in meat processing, and thus can be of aid in designing microbiologically “safe” cooling regimes for uncured chicken and beef meats.