Department of Food Science, Agricultural University Wageningen, 6700 EV Wageningen, The Netherlands.
Appl Environ Microbiol. 1994 Jan;60(1):204-13. doi: 10.1128/aem.60.1.204-213.1994.
The temperature of chilled foods is an important variable for the shelf life of a product in a production and distribution chain. To predict the number of organisms as a function of temperature and time, it is essential to model the growth as a function of temperature. The temperature is often not constant in various stages of distribution. The objective of this research was to determine the effect of shifts in temperature. The suitability and usefulness of several models to describe the growth of Lactobacillus plantarum with fluctuating temperatures was evaluated. It can be assumed that temperature shifts within the lag phase can be handled by adding relative parts of the lag time to be completed and that temperature shifts within the exponential phase result in no lag phase. With these assumptions, the kinetic behavior of temperature shift experiments was reasonably well predicted, and this hypothesis was accepted statistically in 73% of the cases. Only shifts of temperature around the minimum temperature for growth showed very large deviations from the model prediction. The best results were obtained with the assumption that a temperature shift (within the lag phase as well as within the exponential phase) results in an additional lag phase. This hypothesis was accepted statistically in 93% of the cases. The length of the additional lag phase is one-fourth of the lag time normally found at the temperature after the shift.
冷藏食品的温度是产品在生产和分销链中保质期的一个重要变量。为了预测温度和时间对生物体数量的影响，必须将生长建模为温度的函数。在不同的分配阶段，温度通常不是恒定的。本研究的目的是确定温度变化的影响。评估了几种模型来描述温度波动时植物乳杆菌的生长。可以假设，在滞后期内的温度变化可以通过添加要完成的滞后时间的相对部分来处理，而在指数期内的温度变化则不会导致滞后期。在这些假设下，温度变化实验的动力学行为得到了很好的预测，并且在 73%的情况下，这一假设在统计学上是被接受的。只有在生长的最低温度附近的温度变化与模型预测有很大的偏差。在滞后期和指数期内的温度变化导致额外的滞后期的假设下，得到了最好的结果。在 93%的情况下，这一假设在统计学上是被接受的。额外滞后期的长度是在温度变化后的温度下通常发现的滞后时间的四分之一。
