Modelling the effect of a temperature shift on the lag phase duration of Listeria monocytogenes

The aim of this work is to study and model the effect of a temperature shift on h0, the product of the growth rate by the lag phase duration (μλ). Our work is based on the data of Whiting and Bagi [Int. J. Food Microbiol. 73 (2002) 291], who studied the influence of both the pre-incubation temperature (Tprior) and the growth temperature (Tgrowth) on λ values of Listeria monocytogenes. We introduce a new model to describe the evolution of the parameter h0 as a function of Tprior and Tgrowth, and compare it to Whiting and Bagi's published polynomial model that describes the influence of Tprior and Tgrowth on λ independently of μ. For exponential as well as stationary phase cells, h0 increases almost linearly with the magnitude of the temperature shift. A simple linear model of h0 turns out to be more suitable to predict λ values than a polynomial model of λ.