Mycoflora and Mycotoxin of Sorghum grains in Egypt.

Abstract

Ninety-eight fungal species which belong to 35 genera were isolated from preharvest and stored postharvest (40 samples, each) sorghum grains in addition to some cultivars (9) on two isolation media (I% glucose- and 2.1% cellulose-Czapek's agar) at 28 °C. In preharvest grains, 68 species were identified on glucose­ (59 species of24 genera) and cellulose- (56 species of25 genera) Czapek's agar. In stored grains, 38 species belonging to 18 genera were isolated on glucose- (34 species of 18 genera) and cellulose­ (32 species of 18 genera) Czapek's agar. In sorghum grain cultivars, 43 species belonging to 21 genera were collected on glucose- (35 species of 19 genera) and cellulose- (35 species of 18 genera) Czapek's agar. The surface-disinfecting sorghum grains (chlorox and ethyl alcohol) had clear effects on filamentous fungi (quality and quantity) and number of infecting grains. Also, 6 species of 6 genera appeared after surface-disinfection, whereas they were not recorded before treatment. Aflatoxins B 1, B2, G 1 & G2, T-2 toxin and zearalenone were detected in ethyl. acetate extracts of stored sorghum grains (5/40 samples) and cultivars (1/9). Moniliformin naturally appeared in 90% methanol-water extracts of stored grains. Relative humidity (-o%, 76%, 92% and I 00%) had a crucial effect on fungal growth (count and frequency), mycotoxin production (quality and quantity), moisture content and germination capacity of the grains