Modelling the penetration and growth of bacteria in eggs

A model for the penetration of bacteria in eggs have been developed. The model is based on simultaneous transport and growth in three basic zones of the egg: the egg yolk, the albumen and the egg shell. Transport is described by an effective diffusivity mechanism, combined with a first-order linear movement for motile bacteria. Bacterial growth is modelled according to the Baranyi model. Approximate parameter values are obtained by comparing model output with literature data for Salmonella enteritidis. The model output is illustrated by simulations showing the influence of the external shell concentration on the breakthrough through the egg shell.