Postharvest UV-C irradiation for fungal control and reduction of mycotoxins in brown, black, and red rice during long-term storage.

The formation of fungal colonies, mycotoxins, phenolic compounds, cooking quality and color properties were evaluated in freshly-harvested brown, black, and red rice grains and then subjected to ultraviolet radiation (UV-C) for 1 and 3 h. Assessments were made after 6 months of storage. The exposure of black and red rice at 1 h of UV-C was enough to decrease the presence of fungal colonies by 22% and 79%, respectively, without any changes in cooking and coloring properties. In brown rice, only 3 h of UV-C irradiation was able to reduce the formation of fungal colonies. The release of phenolic compounds associated with cell wall was observed only in black and red rice subjected to UV-C radiation. The levels of mycotoxins gradually decreased with the increase in the time of exposure to UV-C radiation, demonstrating UV-C irradiation to be an effective method in fungal control and reduction of mycotoxins in stored rice.