Mycotoxins are poisonous chemical substances produced by molds during their growth on foods, feeds, and various agricultural commodities such as cereal grains, oilseeds, and nuts. The Food and Agriculture Organization (FAO) estimates that at least 25%, and in some areas as much as 50%, of food crops are affected by mycotoxins, with at least 5–10% of the world food supply lost annually to fungi and mycotoxins. In the United States the estimated costs of fungal and mycotoxin contamination of food and feed are between $418 million and $1.66 billion annually.