Aflatoxins are toxic substances that are produced during the metabolic activities of mold, which can grow in a number of foods or raw materials used in the manufacture of edible consumables. They are known to trigger inflammatory changes within the body and give rise to various diseases, including cancer. Aflatoxins have also been strongly associated to the development of liver cirrhosis too. Contamination of feeds with aflatoxins in the past has led to a large number of deaths of birds and animals.
Using thin layer chromatography (TLC), many types of aflatoxins were identified. When examined under ultraviolet light, the aflatoxins B1 and B2 appeared blue, whereas G1 and G2 appeared green. Aflatoxin B1 is the most toxic of these. A major outbreak of acute aflatoxicosis in humans is reported to have occurred in India, way back in the year 1975. The consumption of corn that was contaminated with aflatoxins led to severe sickness in almost a thousand people. Nearly ten percent of them succumbed to the illness.
In the past, many molds from the Penicillium and Rhizopus groups were assumed to produce aflatoxins because many of the substances that they produced had chromatographic and fluorescent properties that were similar to aflatoxins. It was only later that it was realized that these fungi were harmless and the culprits were a small group of closely related aspergilli. Aspergillus flavus, Aspergillus parasiticus, Aspergillus nomius, Aspergillus ochraceoroseus, and Aspergillus pseudotamarii are the fungi have been found to produce aflatoxins. Out of these, the first two are the commonest aflatoxigens.
When cows are fed on foods that are contaminated with Aflatoxin B1, considerable amounts of this aflatoxin are secreted in the milk. This form, which is only slightly less harmful as compared to aflatoxin B1, is referred to as aflatoxin M1. Not so surprisingly, this aflatoxin has also been detected in human milk in some cases. The worst part is that these aflatoxins are heat stable; hence, cooking has no effect on them. So, even if you boil your food really well, you will yet not be able to escape from the ill-effects of aflatoxins is the raw materials that you have used for cooking are contaminated.
Aflatoxins are known to multiple very fast when the postharvest storage conditions are inappropriate. If the crops or their derivatives are dried up quickly and stored in an environment where the water activity is lower than 0.78, the chances of aflatoxigenic molds growing in them will reduce drastically. The temperature and the physical state of the commodity also make a difference. If the temperature is greater than 15° C or the stock is damaged, the risk of aflatoxin formation increases.