Mycotoxins in Feeds and Ingredients and their Origin

Data from many parts of the world on incidence and levels of aflatoxins in feeds and feed ingredients indicate cause for concern, especially in tropical and sub-tropical regions and in those countries importing feedstuffs from these areas. The main products affected are peanut (groundnut) meal, cottonseed products, corn, copra products, and mixed feeds containing any of these components. Reports of the presence of the metabolite aflatoxin M₁ in dairy products provide further evidence of contaminated feeds. Although the main survey effort has been with the aflatoxins, surveys in several countries for other fungal toxins have revealed some contamination of certain grains or pasture grasses with ochratoxin A, citrinin, sterigmatocystin, patulin, penicillic acid, zearalenone, trichothecenes (T-2 toxin, deoxynivalenol, nivalenol, and diacetoxyscirpenol), alternariol and its methyl ether, PR toxin, kojic acid, ergot alkaloids, and sporidesmin. It is important to differentiate between biased and unbiased surveys in evaluation of these data. Mycotoxins usually result from improper storage of feedstuffs, although in certain cases they can also be formed before harvest. Tenuazonic acid has been detected in blast diseased rice plants. Dicoumarol may be produced in sweet clover as a result of fungal activity. Ipomeamarone and related compounds in the sweet potato are examples of toxins synthesized by plants in response to invasion by molds or to other stress conditions.