Worldwide contamination of feeds with fungi and their toxines occurs. Fungal contamination is undesirable because of the formation of mycotoxin. Mycotoxins are metabolites of fungi that have the capacity to impair animal health and productivity. The generic term for these problems is "mycotoxicosis", and include distinct syndromes as well as non-specific conditions. Mycotoxin contamination of forages and cereals frequently occurs in the field following infection of plants with certain pathogenic fungi or with symbiotic endophytes. Contamination may also occur during processing and storage of harvested products and feed whenever environmental conditions are appropriate for spoilage fungi. Moisture content and ambient temperature are key conditions for fungal colonisation and mycotoxin production. It is conventional to subdivide toxigenic fungi into "field" (or plant-pathogenic) and "storage" (or saprophytic/spoilage) organisms. Mycotoxigenic species may be further distinguished on the basis of geographical prevalence, reflecting specific environmental requirements for growth and secondary metabolism.
Even small amounts of mycotoxins can have a detrimental effect on the immune system and metabolism thus posing continuous threat to human and animal health. Nowadays there are companies who develop product which deactivate mycotoxins.