This study evaluated the combined antimicrobial efficacy of a polyvalent bacteriophage and sodium hexametaphosphate (SHMP) against planktonic and biofilm cells of Salmonella Schwarzengrund and Escherichia coli O157:H7. The combined treatment exhibited a synergistic effect, resulting in significantly greater reductions in bacterial populations and biofilm biomass than either treatment alone. The strategy was also effective on food products and food-contact surfaces, demonstrating its potential as a safe and environmentally friendly approach for controlling foodborne pathogens and improving food safety.