** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THIS PROJECT WILL INVESTIGATE BACILLUS CEREUS, A FOODBORNE PATHOGEN COMMONLY FOUND IN THE NATURAL ENVIRONMENT AND FOOD SYSTEMS. BACILLUS CEREUS GROUP BACTERIA ARE PARTICULARLY PROBLEMATIC BECAUSE THEY CAN FORM SPORES THAT RESIST HEAT AND SANITIZERS, WHICH HELPS THEM PERSIST IN FOOD PROCESSING ENVIRONMENTS. THESE BACTERIA HAVE BEEN OF GROWING CONCERN IN BABY FORMULA AND PLANT-BASED FOOD ALTERNATIVES, HIGHLIGHTING THE NEED FOR RESEARCH THAT CAN INFORM RISK-BASED FOOD SAFETY DECISION-MAKING. STRAINS OF B. CEREUS GROUP VARY IN THEIR ABILITY TO PRODUCE DIARRHEAL ENTEROTOXINS, SUCH AS HEMOLYSIN BL, IN HUMAN GUT. HOWEVER, THE CAPACITY OF A STRAIN TO EXPRESS ENTEROTOXINS REMAINS CHALLENGING TO PREDICT. TO IMPROVE OUR ABILITY TO IDENTIFY HIGH-RISK STRAINS, THIS RESEARCH FOCUSES ON IDENTIFYING AND VALIDATING GENETIC VARIANTS IN ENTEROTOXIN GENES THAT PROVIDE B. CEREUS WITH AN INCREASED ABILITY TO PRODUCE ENTEROTOXINS AND CAUSE TOXICITY TOWARDS HUMAN GUT CELLS. IDENTIFIED VARIANTS WILL BE VALIDATED AND INTEGRATED INTO AN EXPOSURE ASSESSMENT MODEL THAT WILL ALSO PROVIDE QUALITATIVE INFORMATION ABOUT FOOD SAFETY RISK POSED BY INDIVIDUAL STRAINS OF B. CEREUS. WE WILL FURTHER INVESTIGATE THE ROLE OF ENTEROTOXIN HEMOLYSIN BL IN SURFACE COLONIZATION AND BIOFILM FORMATION TO ASSESS WHETHER HEMOLYSIN BL HELPS B. CEREUS SURVIVE AND OUTCOMPETE OTHER BACTERIA IN FOOD PROCESSING ENVIRONMENTS. BY UNDERSTANDING HOW HEMOLYSIN BL CONTRIBUTES TO B. CEREUS SURVIVAL AND COMPETITION, WE CAN DEVELOP STRATEGIES TO MITIGATE THE PERSISTENCE OF VIRULENT STRAINS IN FOOD SYSTEMS.