<OL> <LI>Elucidating the ecology (persistence, predominance, behavior, and community analyses) of pathogens in various food matrices, specifically focusing on foods considered high risk by stakeholder regulatory agencies (FSIS/FDA), for example ready-to-eat foods or foods with a short shelf life; <LI>Identifying critical control points for applying interventions, and subsequently developing and validating intervention strategies to be used either alone or in combination with other processes for pathogen control; <LI>Elucidating and defining (including at the molecular level) the physiological responses of pathogens to various food macro and micro-environments then determining intervention strategies and processes, while maintaining food quality.
Approach: Microbiological studies will be conducted with commercial laboratory developed foods to determine how varying food matrices, processing environments, indigenous flora, or conditions associated with food distribution alter the persistence, clonality, or succession of food borne pathogens and threat agents. The predominance, persistence, and succession of pathogens along the food chain and in foods such as ready-to-eat (RTE) meats and poultry products will be determined using conventional and molecular methods to detect and track the microorganisms. Studies will identify critical control points for the application of interventions. Isolates that predominate and persist will be used for inoculated package studies and /or will be evaluated for virulence potential. Food borne pathogens or food security threat agents will be purposefully inoculated into high risk foods (e.g. milk, RTE meats, and cheese) and pathogen viability will be monitored throughout food manufacture and projected shelf life to quantify the lethality of select food processes. Product processing conditions will be identified and used to optimize pathogen destruction and food quality. New and existing microbiological and genomic/proteomic technologies will be used to delineate the genes, proteins, and integrated physiological response networks expressed by food borne pathogens in foods, food related niches, or conditions associated with food processing and storage. The genes for the identified traits or networks will be mutated and these strains will be compared to wild types to assess the importance of the genes and related physiological traits for pathogen survival and growth within foods.