Microbial inactivation and pesticide removal by remote exposure of atmospheric air plasma in confined environments.

Microbial inactivation and pesticide removal by remote exposure of atmospheric air plasma were investigated in confined environments, including an airtight box and commercial refrigerator. The relative sterilization ratios of remote plasma exposure in an airtight box were found to be affected by the distance from the plasma generator, the volume of box and the time of irradiation; however, over 99% saturation was obtained within only 120 s in all experiments. The sterilization of microorganisms and the removal of pesticide in a refrigerator with a volume of 292 l were also successfully achieved, resulting in over 99% inactivation or decontamination in a few minutes. Considering the reported results by direct plasma exposure and circulation, it can be concluded that the confined environment enhances the efficient irradiation of plasma by eliminating air flow. This system can be applied to the storage to keep agricultural products freshly and exclusion of harmful materials on the products.