We
collected 30 samples of cereal crops (Wheat, millet, barley, corn, and rice)
stored and offered for sale in Riyadh area markets. It was found that most of
these samples were contaminated with fungus 
Aspergillus sp.(73.2% ), and that the corn crop was
highest to be hit by fungus Aspergillus sp. (23.3%) compared to
the rest of the crops (wheat 16.6 %), ( barley 13.3%), (millet 10%), and (rice
10%). It appeared in this study that most isolated species have the ability to
produce aflatoxin. We studied the effect of temperature on the secretion of
aflatoxin in isolated fungi; and the results are illustrated in the temperature
table.