Aflatoxins

Aflatoxins

First isolated and characterized after the death of more than 100,000 turkey poults (turkey X disease) traced to the consumption of a mold-contaminated peanut meal. The four major aflatoxins are B₁, B₂, G₁ and G₂ but over a dozen other aflatoxins have been described.

Fungi that produce them

Produced by many strains of Aspergillus flavus and Aspergillus parasiticus; in particular, Aspergillus flavus is a common contaminant in agriculture.

Some less frequently encountered producing species are A. bombycis, A. ochraceoroseus, A. nomius, and A. pseudotamari

Substrates

Natural contamination of cereals, figs, oil- seeds, nuts, tobacco, and a long list of other commodities is a common occurrence.

Sometimes crops become contaminated with aflatoxin in the field before harvest and even more problematic is their storage under conditions that favor mold growth (moisture content of the substrate and relative humidity of the surroundings).

Economic implications

Aflatoxin contamination has been linked to increased mortality in farm animals, lowering the value of grains as an animal feed and as an export commodity.

An indirect source is milk products. When cows consume aflatoxin-contaminated feeds, they biotransform aflatoxin B₁ into a hydroxylated form called aflatoxin M_1.

_{Associated diseases}

Acute aflatoxicosis

Results in death

Chronic aflatoxicosis

Results in cancer, immune suppression, and other slow pathological conditions. The liver is the primary target organ.

Bennett & Klich, 2003, Breitenbach et al 2002, and Peraica et al, 1999.