Fungi may develop in stored grains following field inoculation. In the course oftheir development fungi utilize plant nutrients, contributing to a reduction in their content. This reduction is obviously related to the degree of fungi development, but may become relevant in extreme cases. During the process of host colonization fungi may also produce toxins that are harmful for humans and animals. This occurs mainly under specific conditions of plant stress, such as those produced by adverse weather conditions, for instance drought has been shown to prompt aflatoxin production in peanuts. Differences in mycotoxin production are also related to plant genotype. Aflatoxin B1 produced by Aspergillus flavus is the most carcinogenic natural substance known. It is frequently charged with the reduction in performance of domestic birds, even when its concentration in the feed is very low. Approaches to eliminate mycotoxins from contaminated grains are not always worthwhile in practical and economical terms. Strategies used to reduce mycotoxin levels in cereal grains include the dilution of infected with healthier grains or the addition of adsorbents to the feeds. Several compounds such as activated charcoal, aluminosilicates and processed cell wall of Saccharomyces sp. (esterified glucomannan) have shown to be effective as mycotoxin adsorbents in poultry feeds. Adsorbent effectiveness has been reported with in vitro and in vivo techniques; however, it is still very difficult to quantify their benefits in commercial operations.
