Corradini Maria G, Amézquita Alejandro, Normand Mark D, Peleg Micha
Department of Food Science, Chenoweth Laboratory, University of Massachusetts, Amherst, MA 01003, USA.
Int J Food Microbiol. 2006 Feb 1;106(2):223-8. doi: 10.1016/j.ijfoodmicro.2005.06.014. Epub 2005 Oct 13.
Published experimental isothermal growth curves of Clostridium perfringens cells in ground ham were fitted with a modified three-parameter version of the logistic equation as a primary model and the temperature dependence of the three parameters by ad hoc empirical secondary models. These were used to predict the organism's non-isothermal growth curves under three different cooling regimes. The assumption has been that the organism's instantaneous (or momentary) non-isothermal growth rate is the isothermal rate at the given temperature at a time that corresponds to its instantaneous population size. This could be translated into a differential rate model equation, whose coefficients are constructed from terms that reflect the changing growth parameters with temperature and hence with time. The continuous rate equation, however, can be solved incrementally by a numerical procedure that can be implemented in similar purpose software like Microsoft Excel(R). In all three cases, there was good agreement between the growth curves predicted by the model and those found experimentally. This demonstrated that the procedure can be used to generate growth curves under complicated thermal histories that may include regular and irregular temperature oscillations.
已发表的产气荚膜梭菌细胞在绞碎火腿中的实验等温生长曲线，用逻辑方程的修正三参数版本作为主要模型，并通过特定的经验二级模型来描述这三个参数的温度依赖性。这些模型被用于预测该微生物在三种不同冷却方式下的非等温生长曲线。一直以来的假设是，该微生物的瞬时（或瞬间）非等温生长速率是在对应其瞬时种群大小的某个时间点上，给定温度下的等温速率。这可以转化为一个微分速率模型方程，其系数由反映生长参数随温度进而随时间变化的项构成。然而，连续速率方程可以通过一种数值程序逐步求解，该程序可在类似Microsoft Excel(R)这样的通用软件中实现。在所有三种情况下，模型预测的生长曲线与实验得到的生长曲线之间都有很好的一致性。这表明该程序可用于生成在可能包括规则和不规则温度振荡的复杂热历史条件下的生长曲线。
