Aflatoxins B1, B2, G1 and G2 are difuranocoumarin derivatives produced by a polyketide pathway by many strains of Aspergillus flavus Link. ex Fries, A. parasiticus Speare and A. nomius Kurtzman, B.W.1 These mycotoxins have been found in different food such as corn, peanut, rice and walnut