Ozone as fungicide in rice grains

Abstract

The fungistatic activity, especially during storage, can lead to rapid deterioration in the nutritional quality of grains, and reduce their use and disposal in industrial process due to contamination with toxins (aflatoxins and others). Among the technologies identified as promising in controlling these microorganisms, there is ozonation. The objective of this study was to determine the concentration and the saturation time of ozone gas in rice grains and set the effective ozonation disinfection time in filamentous fungi and yeast. Rice grains (14.3% w.b.) were inoculated with Penicillium spp. and Aspergillus spp. and, subsequently, ozonized at the concentration of 10.13 mg L-1, under continuous flow of 1.0 L min-1, in five periods of exposure (12, 24, 36, 48 and 60 h). Ozone gas concentration and saturation time in rice grains were 5.00 mg L-1 and 13.97 min, respectively. There was a reduction of 3.8 log cycles (100%) in the count of yeasts and complete inhibition of fungal from the genera Aspergillus and Penicillium in ozonized grains.