The antimicrobial effect of the combined UV-A light and benzoic acid (BA) or propyl paraben (PP) treatment was evaluated using Escherichia Coli O157:H7. Factors affecting the efficacy of antimicrobial treatments were examined through various microbial and biochemical approaches. A combined 15 mM BA and UV-A treatment exhibited more than 5 log (CFU/mL) reduction in antimicrobial activity via production of reactive oxygen species (ROS), membrane damage and decreasing intracellular pH. Similarly, the combined 3 mM PP and UV-A treatment also caused more than 5 log reduction contributed by membrane damage. UV-A and BA treatment was also found to be effective in a scaled-up, continuous system, while a combined UV-A and PP was able to significantly reduce the likelihood of cross-contamination in simulated fresh produce washing study. The findings from this study have revealed the potential for the combined treatments that help to improve the safety and quality of fresh produce.