**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** OUR GOAL IS TO PREVENT PATHOGENS FROM GETTING INTO THE FOOD SUPPLY. FOOD PRODUCTION IN THE U.S. OFTEN TAKES PLACE IN LARGE, INDUSTRIAL PLANTS WITH COMPLEX NICHES (I.E. PLACES WHERE PATHOGENS CAN HIDE) THAT RESIST SANITATION EFFORTS. HOWEVER, LITTLE ANALYSIS HAS BEEN DONE ON THE MICROBIAL COMMUNITIES LIVING IN THESE NICHES, INCLUDING WHICH ATTRIBUTES OF THE NICHE DRIVE THE SELECTION FOR PARTICULAR MICROBES. MOST ENVIRONMENTAL SANITATION RESEARCH HAS NOT STUDIED THE ROLE OF SANITIZER FLUID FLOW IN AND OUT OF THE NICHE EVEN THOUGH WE KNOW THAT IT GREATLY IMPACTS MICROBIAL REMOVAL. WE AIM TO RESOLVE THESE UNKNOWNS BY IDENTIFYING AND DEFINING SPECIFIC MICROBIAL COMMUNITIES WITHIN DIFFERENT NICHES TO BETTER UNDERSTAND THE SOURCES OF IMPORTANT FOODBORNE PATHOGENS LIKELISTERIA MONOCYTOGENES. WE WILL COLLECT MORE THAN 1,000 ENVIRONMENTAL SAMPLES FROM THREE LARGE DAIRY PLANTS TO DEFINE THE MICROBIOME OF DIFFERENT NICHES. WE WILL THEN APPLY MACHINE LEARNING ALGORITHMS TO IDENTIFY THE FEATURES MOST PREDICTIVE OF SPECIFIC MICROBIAL TAXA, VERIFYING THESE ASSOCIATIONS USING LABORATORY STUDIES. FINALLY, WE WILL EXPLORE HOW COMPLEX FEATURES OF THE NICHE IMPACT ENVIRONMENTAL SANITATION BY RESTRICTING FLUID FLOW, USING SANITATION CHALLENGE STUDIES TO DETERMINE HOW SANITATION IMPACTS DIVERSE MICROBIAL COMMUNITIES. OVERALL, OUR WORK AIMS TO REDUCE OUTBREAKS AND RECALLS; ADVANCE SOURCE TRACKING AND ROOT CAUSE ANALYSIS AFTER CROSS-CONTAMINATION; AND SUPPORT BETTER DESIGN OF FOOD PLANTS TO STRATEGICALLY ELIMINATE MICROBIAL HARBORAGE POINTS.