Formation of aflatoxins by some Egyptian Aspergillus flavus strains.

In all the fifteen investigated Aspergillus flavus and A. parasiticus strains the maximum quantities of aflatoxins, produced on rice powder-corn steep (RC) medium, ranged from 1.17 to 23.29 times as much as those produced on yeast extract-sucrose (YES) medium. The shake cultures lowered aflatoxin formation. The maximum yields of aflatoxins did not coincide with maximum fungal growth. In most A. flavus strains investigated, the total aflatoxin content of the mycelia highly exceeded that of the culture filtrates.