Mycotoxin

Mycotoxin (from Gk. ????? (mykes) "fungus") is a toxinproduced by a fungusunder special conditions of moistureand temperature. These fungi are aerobic(use oxygen) and microscopicand, moreover, may colonise many kinds of food from the field to the table. Mycotoxins can appear in foodand animal feedas a result of fungal infectionof the crop, for example Fusariumear diseases in cereals, or the infection of stored products. Not all fungi can produce mycotoxins. In addition some fungi are able to produce mycotoxins only in special conditions such as at specific levels of moisture, stress and the correct temperature. Even those with the ability to produce mycotoxins may not produce them all the time. The absence of mycotoxins doesn't ensure the absence of fungal spores, so it's possible for fungi to 'appear' when the temperature and humidity are right. In addition, the mycotoxins are very resistant to temperature treatments and to conventional food processes such as cooking, freezing etc.

Public concern over mycotoxins increased following some of the multi-million dollar "toxic mould" settlements of the late 1990s. The negative health effects of mycotoxins are a function of the concentration, duration of exposure and the subject's sensitivities. The concentrations experienced in a normal home, office or school are typically too low to trigger a health response in occupants. The mycotoxins are not gaseous(non-volatile), but rather they are associated with the spores and hyphae. Exposure typically occurs when contaminated food is eaten. In some cases this may include meat from animals that have themselves been fed contaminated feed.

In Europe, statutorylevels of a range of mycotoxins permitted in food and animal feed are set by a range of European directivesand Commissionregulations.

Classification

Major groups of toxins include:

Aflatoxins produced by Aspergillus species, they are largely associated with commoditiesproduced in the tropicsand sub-tropics, such as groundnuts, other ediblenuts, figs, spicesand maize. Alflatoxin B₁, the most toxic, is a potent carcinogenand has been associated with liver cancer.

OchratoxinA is produced by Penicillium verrucosum, which is generally associated with temperateclimates, and Aspergillus ochraceus which grows in warm humidconditions. It is found as a contaminantof a wide range of commodities including cerealsand their products, dried vinefruit and a wide range of beveragesand spices. It causes kidneydamage in humans and is a potential carcinogen.

Patulin is associated with a range of fungal species and is found in mouldy fruits, vegetables, cereals and other foods. It is destroyed by fermentationand so is not found in alcoholic drinks. It may be carcinogenic and is reported to damage the immune systemand nervous systemsin animals.

Fusarium toxins are produced by several species of the genus Fusarium which infect the grain of developing cereals such as wheatand maize. They include a range of mycotoxins including the Fumonisins, which affect the nervous systemsof horsesand cause cancer in rodents, the Trichothecenes, including deoxynivalenol, and Zearalenone, the last two of which are very stable and can survive cooking. The trichothecenes are acutelytoxic to humans, causing sickness and diarrhoea and potentially death.

Mycotoxins in fiction

A fictional application of a mycotoxin occurs in William Gibson'sseminal novel Neuromancer, in which Case, the anti-hero, is punished by some of his business partners for trying to steal from them by being administered a "Russian mycotoxin", which alters his nervous tissue and renders him unable to access cyberspace.

External links

• Detailed information on different mycotoxins
• Microbiology of Animal Feeds

fr:Mycotoxine ja:マイコトキシン

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Mycotoxin Wikipedia article Mycotoxin.