الفهرس 
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Abstract
Fungi are associated with a threat to human health, hazard to animal wealth and parasites to plant, this fact was established since first half of nineteenth century but not only the growth of these fungi is a problem but the most serious problem is the secondary metabolites (mycotoxins) that these fungi produce in food and feed.
In the present study a total of 500 cereals grains were obtained from different market in Sharkia Governate and examined mycologically the cereals are (rice 150 samples, corn 200 samples, wheat 50 samples and soyabean 100 samples).
Three genera were isolated from the previous cereals samples. Genus Aspergillus was the most predominant among isolates followed by Rhizopus and Penicillum.
Concerning the identified species, Six species of Aspergillus were morphologically identified and classified, as a follows: A.flavus1 was isolated from corn, A.flavus 2 was isolated from rice while, A.niger, A.tamarri, A.nidulans, A.ochraceous and A.fumigatus were isolated from corn, wheat and soyabean.
After detection of the aflatoxinogenic strains by HPLC. It was found that one strains of the Aspergillus isolates was not Aflatoxin producer, while A .flavus 1, A. parasiticus and A. flavus2 were aflatoxins producer. Also it was found that A.flavus 1, A.flavus 2 and A.parasiticus have the nor-1 gene of aflatoxin production after detection by real time PCR but expressed with different amount, while A. oryzea and A. niger hadn’t have the nor-1 gene.