Dynamic modelling of pathogen/antagonist interactions in foods

Current predictive models for foodborne pathogenic or spoilage organisms (termed target organisms) mainly focus on single species microbial evolution. This approach may lead to a significant discrepancy between model predictions and reality, e.g., when neglecting the (potential) influence of the background flora and associated microbial interactions. This paper deals with a specific type of multiple species evolution and interaction, namely, a target organism in the presence of a microbial antagonist, where the latter species inhibits the target's growth through lactic acid production. A novel model is developed, which describes the inhibiting effect of lactic acid on the target in an explicit way. The model is successfully applied to an experimental dataset of the pathogen Yersinia enterocolitica in mono- and coculture with the antagonist Lactobacillus sake. Furthermore, the novel model is compared with a more traditional model in the field of predictive microbiology.