Development of High Quality Cereal Drying and Storage Equipment (Part 2)

Microorganism Control Using Ultraviolet Irradiation and TiO₂

Abstract

In this paper, in order to obtain the condition of practical ultraviolet sterilization, we made a recirculating grain sterilization equipment using ultraviolet irradiation. We investigated the ultraviolet sterilization of microorganism that adhere to the wheat surface. And we examined the quality of those wheat. Moreover, we investigated the sterilization using titanium dioxide attracted attention as a photocatalyst and ultraviolet irradiation.
As a result of sterilization experiment, sterilization time required in order to obtain the sterilization rate of 90% was 6.3hours for bacteria and 5.6hours for fungi under condition of 97W/m² ultraviolet irradiance. In this experiment using ultraviolet irradiation and titanium dioxide, sterilization time required to obtain the sterilization rate of 90% was 4.8hours for bacteria and 4.5hours for fungi. We could shorten the sterilization time. In the quality examination, it was thought that there was little influence on quality by ultraviolet irradiation in this range from the germination test and the amylograph examination.
As a result of calculating ultraviolet radiant energy for 30t of grain, it was estimated as 84MJ.