Modeling the Interactions of Pathogenic and Biocontrol Bacteria for Applications in Foods (9702494)

Lactic acid bacteria which are commonly used in various food fermentations (dairy, meat, vegetables) will be added as biocontrol agents to prevent the growth of pathogenic bacteria in minimally processed foods. If a food protected by this type of biocontrol strategy should spoil due to improper refrigeration or other reasons, the lactic acid bacterium should grow and competitively prevent the growth of potentially harmful bacteria. Although the food may not taste good because of the acid produced, the product would not be unsafe. We have developed a mathematical model that predicts the outcome of the competitive growth of bacteria. The model may be useful in determining which lactic acid bacteria should be chosen as biocontrol agents, and how the growth of selected lactic acid bacteria will affect the growth of pathogenic or disease-causing bacteria. Our research will involve growing both biocontrol and pathogenic bacteria,singly and in mixed culture, in vegetable broth and minimally processed vegetable products. Using the model to help interpret the data from these experiments, we hope to gain insights into which factors such as growth rates, production of inhibitory compounds, or sensitivity of the cells to these inhibitors are most important to the predominance of one bacterial culture over another. While we will primarily investigate biocontrol applications for refrigerated vegetable products, it is hoped that the principles learned in these studies can be applied to biocontrol applications for a variety of foods.