Effect of Ozone on the Inactivation of Yersinia enterocolitica and the Reduction of Natural Flora on Potatoes

Fresh vegetables contaminated with Yersinia enterocolitica have been implicated in foodborne disease outbreaks. Surfaces of vegetables can become contaminated with pathogenic microorganisms through contact with soil, irrigation water, fertilizers, equipment, humans, and animals. One approach to reduce this contamination is to treat fresh produce with sanitizers. In this study, the ability of ozone to inactivate Y. enterocolitica inoculated in water and on potato surfaces was evaluated. Furthermore, the efficacy of ozone in reducing natural flora on whole potato was determined. Total aerobic mesophilic and psychrotrophic bacteria, total coliforms, and Listeria monocytogenes were enumerated. Finally, several disinfection kinetic models were considered to predict Y. enterocolitica inactivation with ozone. Treatments with ozone (1.4 and 1.9 ppm) for 1 min decreased the Y. enterocolitica population in water by 4.6 and 6.2 log CFU ml⁻¹, respectively. Furthermore, ozonated water (5 ppm) for 1 min decreased Y. enterocolitica and L. monocytogenes from potato surfaces by 1.6 and 0.8 log CFU g⁻¹, respectively. Therefore, ozone can be an effective treatment for disinfection of wash water and for reduction of potato surface contamination.