FEMS 2013 - Congress of European Microbiologists edition:5 location:Leipzig, Germany date:21-25 July 2013
In food industry, accurate control of food quality and safety is indispensable. Predictive microbiology constitutes a theoretical framework for this purpose, by developing models to describe microbial dynamics under various environmental conditions. Traditionally, these models are set up as a limited set of equations that describe global cell density. This approach is appropriate for pure cultures with a high cell number in homogeneous liquid media. However, most food products have a matrix structure that hinders cell mobility, which leads to microbial growth in separate colonies.
The goal of this research is the quantitative modeling of microbial colonies. In the colony, substrate depletion and overproduction of metabolites occur, due to high substrate consumption and diffusion limitations of substrate and metabolites. Consequently, cells in the colony exhibit a strongly different individual behavior, according to their position in the colony. In the colony center, this leads to diauxic growth on metabolites and cell inactivation.
In order to incorporate the spatial dependency of the cellular processes, individual-based models consider the cell as the modeling unit, instead of the population. The colony is simulated as a bunch of cells. Its dynamics emerge from cell behavior rules and interactions. The individual-based modeling paradigm is supported by specific software toolkits.
A simulator has been developed to describe quantitative behavior of Escherichia coli K-12 MG 1655. It seems that the software toolkits are not equally suitable to deal with the time-consuming simulation and the implementation of efficient diffusion schemes.