Fungal populations and mycotoxins of wheat grains imported to Egypt

ABSTRACT

The fungal populations and mycotoxins were evaluated on 38 wheat grain samples imported to Egypt from different countries. The incidences, isolation frequencies and relative densities of both storage and field fungi were determined. 61 species and one unidentified species in addition to 3 species varieties appertaining to 21 genera were isolated on glucose-Czapek's agar medium [CZ], glucose-Czapek's agar containing 6% NaCl [CZ-Nacl] and malt agar medium [MA]. The most predominant mycobiota were, Aspergilus species [43.4%] followed by Eurotium species[13.7%], Rhizopus [13.2%], and Alternaria species [7.7%] of the total isolates. The most common species which contaminated samples were A. flavus [18.2%] followed by A. flavus var. columnaris [12.7%], Alternaria alternate [9.3%], and Eurotium amstelodami [3.8%] of the total isolates. Statistical analysis revealed a high significant correlation between, fungal total count, number of genera, and number of species on different media. Meanwhile, the mean number of genera and species on MA and CZ were significantly increased than CZ-NaCl. Evaluation of naturally occurance of mycotoxins in wheat grain, showed 10.5% of samples containing sterigmatocystin. The most predominant mycotoxigenic species were A. flavus var. columnaris and A. flavus. Nevertheless, the ability of Aspergillus of section Flavi to produce mycotoxins [aflatoxins B[1], B[2], G[1] and G[2] and sterigmatocystin] was 35.4% of isolates. These hazardous compounds are known to decrease the food quality and can cause acute of chronic intoxication to humans and animals