FOODBORNE DISEASES ARE A SIGNIFICANT SOURCE OF SICKNESS AND DEATH IN THE UNITED STATES. SHIGA TOXIN-PRODUCING ESCHERICHIA COLI (STEC) O157 IS RESPONSIBLE FOR A PORTION OF THESE CASES. THROUGHOUT CATTLE REARING AND THE SLAUGHTER PROCESS, STEC O157 CONTAMINATION OF FOOD PRODUCTS CAN OCCUR, RESULTING IN TRANSMISSION TO HUMANS AND DISEASE. INTERVENTIONS ARE ONE WAY TO REDUCE STEC O157 IN CATTLE AND REDUCE THE RISK OF INFECTION IN HUMANS. BACTERIOPHAGE (PHAGES) ARE VIRUSES THAT INFECT BACTERIA AND, IN CERTAIN INSTANCES, CAN KILL THEM. DUE TO THEIR HIGH HOST SPECIFICITY, PHAGES ARE HARMLESS TO MAMMALIAN CELLS AND ARE AN ALTERNATIVE TO ANTIBIOTICS. PHAGES ARE UBIQUITOUS IN ENVIRONMENTS, AND UNLIKE OTHER INTERVENTIONS, ARE NOT MAINTAINED WITHOUT A BACTERIAL HOST. THIS PROPERTY MAKES THEM AN ATTRACTIVE POSSIBILITY TO USE AS AN INTERVENTION AGAINST STEC O157.THE APPROACH IN THIS PROPOSAL IS TO IDENTIFY A COCKTAIL OF PHAGES THAT WILL ELIMINATE A STEC O157 STRAIN IN LIQUID AND CELL CULTURE. THISCOCKTAIL ALSO WILL BE USED IN CATTLE COLONIZED WITH STEC O157 TO DETERMINE IT'S EFFECTIVENESS IN REDUCING SHEDDING. WE WILL ALSO DEVELOP A COMPUTER LEARNING APPROACH TO PREDICT WHAT PHAGE COCKTAILS WILL WORK AGAINST DIFFERENT STRAINS OF STEC O157. THE ULTIMATE GOAL OF THIS PROPOSAL IS TO PROVIDE AN INTERVENTION FOR THOSE WHO RAISE CATTLE TO REMOVE OR REDUCE STEC O157 SHEDDING IN CATTLE. THIS INTERVENTION WOULD REDUCE THE AMOUNT OF STEC O157 ENTERING THE FOOD CHAIN AND PROVIDING A SAFER FOOD SUPPLY.