Aflatoxin

Description

Aflatoxins are naturally occurring bisfuranocoumarin compounds produced from the molds Aspergillus flavus and Aspergillus parasiticus. The aflatoxins are highly fluorescent. The B refers to blue and the G signifies green fluorescence. M aflatoxins are fungal metabolites present in milk. Aflatoxin B1 is the most common and potent of the aflatoxins. Crops that are affected by aflatoxin contamination include cereals (maize, sorghum, rice, wheat), oilseeds (peanut, sunflower, soybean, cotton), spices (chili peppers, black pepper, coriander, turmeric, ginger), and tree nuts (almond, coconuts, brazil nuts, walnuts, pistachio). Aflatoxin can also be found in the milk, eggs, and meat from animals fed contaminated feed.

Chemical Properties

The aflatoxins are a group of molds produced by the fungus Aspergillus flavus. They are natural contaminants of fruits, vegetables, and grains. They are also described as a series of condensed ring heterocyclic compounds. They form colorless to pale yellow crystals. Practically insoluble in water.

Uses

Aflatoxins are used solely for research purposes. They are naturally occurring contaminants formed by certain fungi on agricultural crops, first discovered in the 1960s (IARC 1976).

Definition

Toxic metabolites produced by fungi.

Safety Profile

Confirmed human carcinogen with experimental tumorigenic data. Human poison by ingestion. An experimental teratogen. Other experimental reproductive effects. Mutation data reported. See also various aflatoxins

Potential Exposure

Aflatoxins are a group of toxic metabolites produced by certain types of fungi. Aflatoxins are not commercially manufactured; they are naturally occurring contaminants that are formed by fungi on food during conditions of high temperatures and high humidity. Most human exposure to aflatoxins occurs through ingestion of contaminated food. The estimated amount of aflatoxins that Americans consume daily is estimated to be 0.15 0.50 μg. Grains, peanuts, tree nuts, and cottonseed meal are among the more common foods on which these fungi grow. Meat, eggs, milk, and other edible products from animals that consume aflatoxincontaminated feed may also contain aflatoxins. Aflatoxins can also be breathed in

Carcinogenicity

Aflatoxins are known to be human carcinogens based on sufficient evidence of carcinogenicity from studies in humans. Aflatoxins were listed in the First Annual Report on Carcinogens as reasonably anticipated to be human carcinogens based on sufficient evidence of carcinogenicity from studies in experimental animals and limited evidence of carcinogenicity from studies in humans; however, the listing was revised to known to be human carcinogens in the Sixth Annual Report on Carcinogens in 1991.

Environmental Fate

Aflatoxin B1 is metabolized to a reactive epoxide (aflatoxin 8,9-epoxide) primarily by the P450 monooxygenase system. In humans, the epoxidation reaction is catalyzed by CYP1A2 and CYP3A4. Once formed, the epoxide can react further to form DNA adducts (aflatoxin-N7-guanine) and induce mutations and cancer. Alternatively, the epoxide can be detoxified by conjugation with glutathione through the actions of certain glutathione S-tranferases. Rats are more susceptible than mice to aflatoxin hepatocarcinogenesis even though both species form the reactive 8,9-epoxide at similar rates. Differences in species susceptibility are hypothesized to relate to increased rates of glutathione conjugation to the aflatoxin 8,9-epoxide in mice compared to rats.

Shipping

UN3172 Toxins, extracted from living sources, solid or liquid, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Toxicity evaluation

Aflatoxin will exist solely in the particulate phase if released into the ambient atmosphere based on estimated vapor pressure values (1.6 ×10
^-10 to 7.7×10
^-11mmHg) at 25°C. Particulate-phase aflatoxins would be expected to be removed from the atmosphere by wet and dry deposition. Direct photolysis is also possible since aflatoxins absorb light in the environmental UV spectrum. If released to soil, the aflatoxins are expected to have high to slight mobility based upon Koc values of 3974, 263, and 116. Aflatoxins are not expected to volatilize from dry soil surfaces based upon their vapor pressures. If released into water, the aflatoxins may adsorb to suspended solids and sediment based upon the available Koc values. Estimated BCF values of 2–3 suggest the potential for bioconcentration in aquatic organisms is low. Aflatoxin may also be degraded by photolysis at soil and water surfaces.

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

Waste Disposal

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Use of oxidizing agents, such as hydrogen peroxide or 5% sodium hypochlorite bleach. Acids and bases may also be used.