Mycobiota and Mycotoxins Contaminating Rice Grains in El Minia, Governorate, Egypt

Abstract

The mycological analysis of 51 samples of rice grains collected from different localities in El-Minia Governorate revealed the isolation of 54 species of fungi belonging to 21 genera. Most common mycobiota (genera) were Aspergillus and Penicillium being isolated from 96.07% and 54.9% of samples contributing 63.08% and 21.89% of total fungal counts. The prevalent species were represented by Aspergillus flavus, A. candidus, A. niger, Penicillium chrysogenum, P. islandicum especially on Dichloran Rose Bengal Chloramphenicol Agar medium (DRBC). These species in addition to some osmophilic fungi including A. chevalieri, A. montevidensis, A. rubrum were also common when Dichloran Glycerol agar (DG18) was used for the culturing of rice samples. About 12.5% of samples analysed for natural occurrence of mycotoxins were contaminated either with Aflatoxin – B1 (100-200 µg/ kg), ochratoxin –A (50-100 µg/ kg) or sterigmatocystin (10-20 µg/ kg). The majority of fungal strains tested for their mycotoxin production in liquid cultures were able to produce variable levels of aflatoxin B1, Aflatoxin G1 , Ochratoxin –A , terrein , gliotoxin and fumagillin