A parallel study on bacterial growth and inactivation.

Pure stochastic birth process models are used to establish the connection between the traditional food microbiology concept of bacterial lag period, before the exponential growth, and the distribution of the lag times of individual cells. In a parallel way, similar study is carried out on the connection between the "shoulder" period, before the exponential decay, and the distribution of the survival times of individual cells. Formulae are derived to calculate the parameters of the growth/survival curves from the distributions of the respective parameters of individual cells. It is shown that, in some aspects, analogy, in some aspects fundamental difference exists between growth and survival modelling.