Modeling of Clostridium perfringens vegetative cell inactivation in beef-in-sauce products: a meta-analysis using mixed linear models

The aim of the present study was to predict Clostridium perfringens vegetative cell inactivation during the final reheating step of two beef-in-sauce products prepared and distributed in a French hospital for exposure in risk assessment. In order to account for variability according to experts and international organization recommendations, published data were used to estimate the thermal inactivation parameters of a probabilistic model. Mixed effects models were proposed to describe variability on D(ref) the decimal reduction time at temperature T(ref). Many models differing by their description of variability on D(ref) were tested. Based on goodness-of-fit and parsimony of the model, the one including three random effects was chosen. That model describes random effects of vegetative cell culture conditions, strains and other uncontrolled experimental factors. In order to check the ability of the model to predict inactivation under dynamic thermal conditions, model validation was carried out on published non isothermal data. This model was then used to predict C. perfringens vegetative cell inactivation using temperature profiles inside beef-in-sauce products registered in a French hospital and to explore control measures easier to apply than French regulations.