Virulence of non-culturable and persistent food borne pathogens

Hypothesis: NC pathogens are unwittingly induced using common food processing conditions that enable persistence of these metabolically different and undetectable organisms in food and the food processing environment using common plating methods.ObjectivesAim 1: Induce the NC state in Salmonella and Listeria. We will use methods described here to induce NC in both genera. Verification will be done as described with plate counts, PCR and ATP concentration to define the point of switch to NC from active growth.Aim 2: Determine the induced metabolic changes of NC pathogens. Once the pathways and genes are defined to be important in NC induction, their distribution in the genus will be determined using a population genome comparison. This result will enable identification of new diagnostic genes (or transcripts) to find NC pathogens in the food chain.Aim 3: Determine the ability of NC pathogens to resuscitate, express virulence, and produce adhesion factors using gut epithelial cells (gut association) and immune cells (mesenchymal stem cells) association. Using host association models and gene expression we will examine the exact gene targets for use in food. Specific mammalian-derived products (serum, bone marrow, etc.) will be added to examine resuscitation. We will specifically look for NC initiation, resuscitation, and metabolic routes that can be targets for reducing NC FBP.Aim 4: Determine bacteriophage infection for NC cells of Salmonella and Listeria. It is unknown if phage can be used to control NC cells, even though phage can infect NC cells. This aim seeks to determine the infection dynamics as a point of control for NC pathogens in the food chain.