THE NUMBER OF FOODBORNE DISEASE OUTBREAKS ASSOCIATED WITH FRESH PRODUCE HAS INCREASED RECENTLY IN THE UNITED STATES. HOWEVER, CURRENT POSTHARVEST WASHING AND SANITIZATION PROCESSES DO NOT ALWAYS EFFECTIVELY REDUCE PATHOGEN CONTAMINATION IN/ON PRODUCE. THERE IS ALSO INCREASING CONCERN ABOUT THE CHEMICAL COMPOUNDS USED IN POSTHARVEST SANITATION. THEREFORE, NOVEL CONTROL METHODS ARE CRITICALLY NEEDED. TO IMPROVE THE FOOD SAFETY WHILE ELIMINATING THE POSTHARVEST SANITATION, THIS PROOF-OF-CONCEPT PROJECT TACKLES THE USE OF ENDOPHYTIC BACTERIA FOR THE COMPETITIVE EXCLUSION OF POTENTIAL HUMAN PATHOGENS IN/ON FRESH PRODUCE. ENDOPHYTIC BACTERIA ARE SYMBIOTIC, CAN LIVE INSIDE PLANTS FROM FARM TO TABLE, AND ARE BELIEVED TO BE ABLE TO PROTECT PRODUCE AGAINST POTENTIAL HUMAN PATHOGENS FROM PRE- TO POSTHARVEST. LETTUCE AND HUMAN PATHOGEN E. COLI O157:H7 ARE SELECTED FOR THIS STUDY TO PROVE THE CONCEPT OF THE IN SITU BIOCONTROL OF HUMAN PATHOGENS. IN A PRELIMINARY STUDY, WE ISOLATED STRAINS OF PSEUDOMONAS SPP. FROM THE DOMINANT ENDOPHYTES OF LETTUCE USING THE INTERNAL TISSUES OF LETTUCE. NINE STRAINS OF P. FLUORESCENS AND P. KOREENSIS DEMONSTRATED IN VITRO INHIBITORY ACTIVITY AGAINST E. COLI O157:H7. WE PROPOSE TO EXPLORE THE POTENTIAL OF USING THE NINE ISOLATES AS BIO-FERTILIZER FOR SAFEGUARDING LETTUCE. THE ENDOPHYTES' EFFICACY WILL BE EVALUATED IN LETTUCE AGAINST E. COLI O157:H7 IN/ON LETTUCE BEFORE, AT, AND AFTER LETTUCE IS HARVESTED. SUCCESS OF THIS PROJECT CAN PROVIDE AN ENVIRONMENTALLY SOUND, USER-FRIENDLY, AND ECONOMICAL TECHNOLOGY TO IMPROVE THE FOOD SAFETY OF PRODUCE. THIS STUDY CORRESPONDS TO THE OBJECTIVES OF AFRI'S PROGRAM AREA PRIORITY (CODE: A1332): FOOD SAFETY AND DEFENSE.