Mycotoxin

Mycotoxin (from Gk. mykes "fungus") is a toxin produced by a fungus under special conditions of moisture and temperature. These fungus are aerobic (use oxygen) and microscopic and, moreover, may colonise many kinds of food from the field to the table. Mycotoxins can appear in food and animal feed as a result of fungal infection of the crop, for example Fusarium ear diseases in cereals, or the infection of stored products. Not all fungi can produce mycotoxins. In addition some fungus 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 occurs when someone inhales fungal spores.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In Europe, statutory levels of a range of mycotoxins permitted in food and animal feed are set by a range of European directives and Commission Regulations.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Major groups of toxins include

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Aflatoxins produced by Aspergillus species, they are largely associated with commodities produced in the tropics and sub-tropics, such as groundnuts, other edible nuts, figs, spices and maize. Alflatoxin B1, the most toxic, is a potent carcinogen and has been associated with liver cancer.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Ochratoxin A is produced by Penicillium verrucosum, which is generally associated with temperate climates, and Aspergillus ochraceus which grows in warm humid conditions. It is found as a contaminant of a wide range of commodities including cereals and their products, dried vine fruit and a wide range of beverages and spices. It causes kidney damage 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 fermentation and so is not found in alcoholic drinks. It may be carcinogenic and is reported to damage the immune system and nervous systems in animals.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Fusarium toxins are produced by several species of the genus Fusarium which infect the grain of developing cereals such as wheat and maize. They include a range of mycotoxins including the Fumonisins, which affect the nervous systems of horses and 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 acutely toxic to humans, causing sickness and diarrhoea and potentially death.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

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

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Toxin: A toxin, in a scientific context, is a biologically produced substance that causes injury to the health of a living thing on contact or absorption, typically by interacting with biological macromolecules such as enzymes and receptors. Toxicity may be acute (as in a bee sting), chronic (as in the Gua...

Moisture: Moisture generally refers to the presence of water in trace amounts. It is found in several different forms, which can cause rot in wood or other organic material, corrosion in metals, and electrical short circuits....

Temperature: Temperature is the physical property of a system which underlies the common notions of "hot" and "cold"; the material with the higher temperature is said to be hotter. Temperature is a measure of the average kinetic energy of the particles in a sample of matter. In other words, temperature is a meas...