Aflatoxins are naturally occurring secondary metabolite poisonous toxins that are produced by strains of fungi species Aspergillus worldwide. This toxin was discovered 30 years ago in England during a poisonous outbreak that led to the death of over 100,000 Turkeys. The word “Aflatoxins” originated from the name of one of the fungi producing it, Aspergillus flavus. They contaminate 25% food crops worldwide and therefore pose a serious health risk on both humans and animals. The main
aflatoxigenic fungi which are A flavus, A parasiticus, and A nomius are majorly found in soils and decaying vegetation. They occur in warmer parts of the world such as the tropical region where temperature and moisture are high. These fungi survive temperature ranges from 12 – 48 ᵒC and at a humidity range of 0.83 – 0.97.
Physico-chemical properties of aflatoxins
Aflatoxins are chemically stable, and they do not undergo degradation under a normal cooking temperature which makes them difficult to eliminate once they are present in food. They are colorless, odorless and tasteless. They are slightly soluble in water, insoluble in non-polar solvents but soluble in polar organic solvents.
More than 14 isomers of aflatoxins have been discovered but four - B1, B2, G1, and G2 pose several health risks on humans and animals. These 4 isomers are found mostly in nuts, grains, and their byproducts. Also, the hydroxylated metabolite of B1 known as M1 is found in milk and milk products.
Toxicity of aflatoxins
Acute toxicity of these toxins in human can result in vomiting, jaundice, and fever while the chronic toxicity can cause liver carcinogenic, mutagenic and genotoxic. In animals, they cause liver and kidney damage, impaired productivity, stunted growth and in the case of chickens, there is a decrease in egg production.
Aflatoxins are produced in the laboratory for research purposes by fermentation of A flavus or A parasiticus on media. They are extracted by solvents and purified by chromatography method.
Fermentek, a biotechnology company are expert in production of different types aflatoxins and their metabolites in bulk commercially for research purposes. This company focused on production of ten
different aflatoxins. They include: aflatoxicol, a reduced form of aflatoxins B1 used for cancer research purpose, aflatoxin B1, B2, M1, M2 - they are used for food toxicity test.