Postcollection enhancement of mycotoxins and postharvest handling of samples.

Postcollection enhancement of mycotoxins in food samples can occur extremely rapidly at moisture levels above 13-13.5%. The "storage fungi," principally the genera Aspergillus and Penicillium, are capable of rapid growth and potential mycotoxin production at specific moisture levels from 13.5 to 18-20% moisture, whereas "field fungi," such as the genera Fusarium and Pithomyces, may become the predominant species and produce their characteristic mycotoxins at higher moisture levels. Moisture content and temperature are the primary environmental factors conditioning mold growth, although once growth has occurred, mycotoxin production per se may be affected by feed addition. Postharvest handling of samples to ensure safe storage requires that the samples either be rapidly dried to moisture levels below the minimum or be maintained dry. Certain chemicals may be used to inhibit mold growth.