Studies on the formation of aflatoxin M1 in bakery products. Mycotoxins in foodstuffs. XIII.

The aflatoxinogenic moulds Aspergillus flavus NRRL 3251, A.parasiticus CMI 89717 and A.parasiticus NRRL 2999 are able to grow on various types of bread, yet, only the last fungus can produce aflatoxin M1 on these substrates. The highest yields (4 micrograms/kg) of the toxin were found on whole wheat bread at a "Säuregrad" (total acid content) of 5-6 and at an incubation temperature of 30 degrees C. The toxin levels decreased with increasing time of growth; this was probably due to a further metabolism of aflatoxin M1. A.flavus NRRL 3251 and A.parasiticus CMI 89717 grew better and produced more toxin on cake ("Rührkuchen") with aw 0.92 than on cake with lower water activity.