Hydroxyl-radical activated water for inactivation of Escherichia coli O157:H7, Salmonella and Listeria monocytogenes on germinating mung beans.

The following reports on the generation of hydroxyl-radical activated water prepared by passing a hydrogen peroxide solution containing Fe (III) catalyst through a UV-C reactor. The activated water was subsequently evaluated for antimicrobial activity against Escherichia coli O157:H7 in suspension or when inoculated onto mung beans. Hydroxyl-radical generation was assessed through the oxidation of methylene blue when reacted with activated water prepared from solutions of different pH (4-10), UV-C dose (32-128 mJ/cm²), hydrogen peroxide (0-1000 mg/L) and Fe (III) concentration (0-100 mg/L). Methylene blue oxidation was associated with high concentrations of each reactant with a positive correlation with Fe (III) concentration. Inactivation curves of E. coli O157:H7 in activated water were diphasic with an initial slow rate that increased after 15 min contact time. In contrast to the methylene blue assay, the antimicrobial action of activated water was associated with high hydrogen peroxide (500 mg/mL) and low Fe...