Aflatoxin

Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly Aspergillus species mainly by Aspergillus flavus and Aspergillus parasiticus. According to the USDA, "They are probably the best known and most intensively researched mycotoxins in the world."^[1] The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, maize, peanuts, coffee, wheat, millet, sorghum, cassava, rice, chili peppers, cottonseed, tree nuts, sesame seeds, sunflower seeds, and various cereal grains and oil seeds. In short, the relevant fungi grow on almost any crop or food. When such contaminated food is processed or consumed, the aflatoxins enter the general food supply. They have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Animals fed contaminated food can pass aflatoxin transformation products into milk, milk products, and meat.^[2] For example, contaminated poultry feed is the suspected source of aflatoxin-contaminated chicken meat and eggs in Pakistan.^[3]

Children are particularly vulnerable to aflatoxin exposure, which is linked to immune suppression, stunted growth,^[4] delayed development,^[5] aflatoxicosis,^[6] food spoilage and liver cancer. Some studies have reported an association between childhood stunting and aflatoxin exposure, although this link has not been consistently detected in all studies.^{[7][8][9][10]} Furthermore, a causal relationship between childhood stunting and aflatoxin exposure has yet to be conclusively shown by epidemiological studies, though such investigations are underway.^[11][12][13] Adults have a higher tolerance to exposure, but are also at risk. No animal species is known to be immune. Aflatoxins are among the most carcinogenic substances known.^[14] After entering the body, aflatoxins may be metabolized by the liver to a reactive epoxide intermediate or hydroxylated to become the less harmful aflatoxin M₁.

Aflatoxin poisoning most commonly results from ingestion, but the most toxic aflatoxin compound, B₁, can permeate through the skin.^[15]

The United States Food and Drug Administration (FDA) action levels for aflatoxin present in food or feed is 20 to 300 ppb.^[16] The FDA has had occasion to declare both human and pet food recalls as a precautionary measure to prevent exposure.

The term "aflatoxin" is derived from the name of the species Aspergillus flavus, in which some of the compounds first were discovered. A new disease was identified with unknown characteristics in England during the 1950s and 1960s, which increased turkey mortality. Later, aflatoxin was recognized in 1960 in England as a causative agent of the mysterious Turkey ‘X’ disease that causes excessive mortality in turkey poults.^[17] Aflatoxins form one of the major groupings of mycotoxins, and apart from Aspergillus flavus various members of the group of compounds occur in species such as Aspergillus parasiticus, Aspergillus pseudocaelatus, Aspergillus pseudonomius, and Aspergillus nomius.^[18]