Methods of Inactivation for Foodborne Pathogens: an investigation into ozone gas and UV irradiation

These studies were conducted to investigate the efficacy of two disinfectant methods, ozone and UV irradiation, against Escherichia coli and Eimeria acervulina under specified conditions. Ozone gas is a widely studied disinfectant, however, inconsistencies in reporting ozone mass used in treatment as well as differences in log reduction for similar methods has led to complexity in the direct comparison of studies. The objective of this study was to elucidate the sanitizing potential of ozone gas and UV light. 10 to the 6CFU/mL E. coli dried on a stainless-steel surface was exposed to 10 parts per million by volume ozone gas in air across three time points. Log reduction for E. coli after treatment with 10 ppm by mass ozone gas for ninety minutes was found to be 1.65 log; reduction decreased as time decreased. Eimeria acervulina was used as a surrogate for Cyclospora cayetanensis, a foodborne pathogen that infects humans. In recent years, incidences of Cyclospora contamination on crops has been increasing. This recent increase has prompted a search for novel methods of inactivation of the parasite. Eimeria oocyts were treated under 254 nm UV-C light for 1, 3, and 5 minutes. In a separate experiment, oocysts were treated with up to 4.93 ppm by mass ozone bubbled in water. Oocysts treated with UV and aqueous ozone were found to sporulate significantly less than those used as a control.