[Possible contamination of rice grains by mycotoxins in a temperate climate]

The authors studied formation of mycotoxins (aflatoxins B1, B2, G1, G2, ocher toxin A, sterigmatocystine, patulin, toxins T-2 and HT-2, zearalenon. penicillic and kojic acids) under the conditions of experimental storage of rice grain, which was demonstrated to be comparatively resistant to contamination with mycotoxins. Analysis of 208 samples of rice grain of normal quality did not reveal any mycotoxins. In 130 samples taken from the batches subjected to experimental self-heating, aflatoxin B1 was found in 9-10% of cases in concentrations from 16 to 330 micrograms/kg. Sixty-seven per cent of the contaminated samples contained an insignificant amount of aflatoxin B1 (less than or equal to 50 micrograms/kg). Aflatoxin G1, zearalenon, penicillic and kojic acids were discovered in individual samples. Aflatoxins B1 and G1 were accumulated in the rice grain with an initial moisture of greater than or equal to 16%. The amount of aflatoxins and Aspergillus flavus reached a maximum when the temperature of the grain mass was 35-45 degrees C. The authors demonstrated that the toxins in the bulk grain distributed uniformly and described the features of their formation in rice grain, linked with the protective role of the floral film. Provided the data on the toxigenous potential of the microscopic fungi isolated from rice grain. Indicated that during the processing of rice grain, one can see a substantial effect of decontamination, being equal to 88% upon production of rice groats and to 37% upon culinary treatment of rice. Demonstrated that hydrothermal treatment leads to the destruction of over 90% of aflatoxin B1.(ABSTRACT TRUNCATED AT 250 WORDS)