THE HUMAN POPULATION IS EXPECTED TO REACH 9.1 BILLION BY 2050, LIKELY INCREASING THE DEMAND FOR NUTRITIOUS AND SAFE FOOD. CONSUMING FRESH FRUITS AND VEGETABLES IS PART OF AN INTEGRATED STRATEGY TO DECREASE THE RISK OF SERIOUS DISEASES, AND THE CONSUMPTION OF FRESH PRODUCE HAS BEEN INCREASING WORLDWIDE OVER THE PAST FEW DECADES. IN ACCORDANCE, THE EXPANSION OF FRESH MARKETS HAS RESULTED IN A WIDE VARIETY OF FRESH FRUIT AND VEGETABLES BEING AVAILABLE THROUGHOUT THE YEAR. CONCOMITANTLY, THE NUMBER OF FOODBORNE DISEASE OUTBREAKS RELATED TO THE CONSUMPTION OF CONTAMINATED FRESH OR MINIMALLY PROCESSED PRODUCE HAS BEEN INCREASING.MORE THAN 9 MILLION FOODBORNE ILLNESSES IN THE UNITED STATES ARE ESTIMATED TO BE CAUSED BY MAJOR PATHOGENS EACH YEAR. A RECENT ANALYSIS OF ILLNESSES IN 4,589 OUTBREAKS THAT OCCURRED BETWEEN 1998 AND 2008 REVEALED THAT APPROXIMATELY 51% (4.9 MILLION ILLNESSES) WERE ATTRIBUTED TO PLANT COMMODITIES, WHEREAS ~42% (4.0 MILLION ILLNESSES) WERE ATTRIBUTED TO LAND ANIMAL COMMODITIES. AMONG THE 17 COMMODITIES ANALYZED, LEAFY VEGETABLES WERE ASSOCIATED WITH THE MAJORITY OF ILLNESSES (2.2 MILLION; 22%). IN PARTICULAR, ENTEROHEMORRHAGIC ESCHERICHIA COLI (EHEC) AND SALMONELLA ENTERICA ARE THE MOST COMMON CAUSAL AGENTS OF FOODBORNE ILLNESS ASSOCIATED WITH THE CONSUMPTION OF FRESH LEAFY VEGETABLES. IN THE US, NON-TYPHOIDAL SALMONELLA IS THE LEADING CAUSE OF HOSPITALIZATIONS AND DEATH FROM FOODBORNE ILLNESSES, AND E. COLI HAS BEEN ASSOCIATED WITH SERIOUS MULTI-STATE OUTBREAKS THAT COST MILLIONS OF DOLLARS TO THE FRESH PRODUCE INDUSTRY.HUMAN PATHOGENS CAN BE INTRODUCED INTO THE PRIMARY FOOD PRODUCTION CHAIN BY DIFFERENT SOURCES, SUCH AS LOW-QUALITY IRRIGATION WATER, USE OF CONTAMINATED ORGANIC FERTILIZERS, CLOSE PROXIMITY TO LIVESTOCK OPERATIONS, WILDLIFE INTRUSIONS, IMPROPER WORKER HYGIENE, OR CONTAMINATED EQUIPMENT. FRESH PRODUCE CAN BECOME CONTAMINATED DURING PRODUCTION, AT THE PROCESSING/PACKING STAGE, AND/OR DURING PREPARATION. PRE-HARVEST CONTAMINATION MAYBECOME A POST-HARVEST DISASTER RESULTING IN THE INTRODUCTION OF PATHOGENS INTO THE PROCESSING PLANT, ESTABLISHMENT OF BIOFILMS ON FOOD-CONTACT SURFACES, AND SUBSEQUENT CROSS-CONTAMINATION OF PRODUCE TO BE DISTRIBUTED AT NATIONAL OR INTERNATIONAL SCALES, LEADING TO MULTI-NATIONAL OUTBREAKS. THUS, GOOD AGRICULTURAL PRACTICE, GOOD HANDLING PRACTICES, GOOD MANUFACTURING PRACTICE, AND HAZARD ANALYSIS OF CRITICAL CONTROL POINTS REMAIN THE CORNERSTONE OF FOOD SAFETY MANAGEMENT ALONG THE PRODUCTION CHAIN (FROM FARM TO FORK) AS PART OF "MULTIPLE HURDLE" APPROACHES TO LIMIT PRODUCE CONTAMINATION. ADDITIONALLY, THE U.S. FOOD AND DRUG ADMINISTRATION HAS PROMULGATED FOOD SAFETY RULES THAT FOCUS ON PREVENTION THROUGH THE FOOD SAFETY MODERNIZATION ACT, PRODUCE SAFETY RULE (HTTPS://WWW.FDA.GOV/FOOD/FOOD-SAFETY-MODERNIZATION-ACT-FSMA/FSMA-FINAL-RULE-PRODUCE-SAFETY).UNLIKE FOODS OF ANIMAL ORIGIN, FRESH OR READY-TO-EAT PRODUCE, SUCH AS LEAFY VEGETABLES, CANNOT UNDERGO THERMAL PROCESSES TO INACTIVATE HUMAN PATHOGENS. DECONTAMINATION TREATMENTS RELY MAINLY ON THE USE OF WASH WATER DISINFECTANT TREATMENTS, USUALLY HYPOCHLORITE. ALTHOUGH SUSPENSIONS OF FOODBORNE PATHOGENS, SUCH AS E. COLI AND S. ENTERICA ARE HIGHLY SUSCEPTIBLE TO COMMERCIAL DISINFECTANTS AT THE RECOMMENDED DOSES AND EXPOSURE TIMES, DISINFECTANTS FAIL TO COMPLETELY ERADICATE PATHOGENS FROM FRESH PRODUCE. CONSEQUENTLY, THE LACK OF AN EFFICIENT KILL-STEP IS A RISK FACTOR AND ONE OF THE GREAT CHALLENGES FACING THE FRESH PRODUCE INDUSTRY. THERE ARE SEVERAL PLAUSIBLE EXPLANATIONS FOR TOLERANCE OF PLANT-ASSOCIATED BACTERIA TO SANITATION PROCEDURES, INCLUDING (A) FORMATION OF BIOFILMS ON THE PLANT SURFACE, (B) RESIDING ON SURFACE-PROTECTED NICHES AND WOUNDS, AND (C) ENDOPHYTIC LOCALIZATION. THUS, POST-HARVEST SANITATION OF FRESH PRODUCE IS NOT SUFFICIENT FOR THE COMPLETE ELIMINATION OF FOODBORNE PATHOGENS FROM PRODUCE. PREVENTION OF PRE-HARVEST CONTAMINATION ON THE FARM IS ONE OF THE MOST IMPORTANT STEPS IN REDUCING HUMAN HEALTHRISK AND IMPROVING FOOD SAFETY.THE US NATIONAL INSTITUTE OF FOOD AND AGRICULTURE (NIFA) HAS A GOAL TO REDUCE FOOD-BORNE ILLNESSES TO 8.5 CASES PER 100,000 AMERICANS PER YEAR (HTTPS://NIFA.USDA.GOV/). ALTHOUGH SEVERAL PROCEDURES ARE IN PLACE TO PREVENT FOOD POISONING, ADDITIONAL CONTROL MEASURES ARE STILL NEEDED TO REDUCE THE NUMBER OF OUTBREAKS, INCLUDING GENETIC RESISTANCE. THIS RESEARCH WILL ADDRESS THE GENETIC MECHANISMS THAT ALLOW E. COLI O157:H7 AND S. ENTERICA TO PERSIST IN THE LEAF ENVIRONMENT, A TRAIT THAT IS LARGELY CONTROLLED BY GENETIC FACTORS IN BOTH THE PLANT HOST AND THE BACTERIAL PATHOGEN.