Mycotoxin
From Wikipedia, the free encyclopedia
Mycotoxin (from Gk. μύκης (mykes, mukos) "fungus") is a toxin produced by an organism of the fungus family, which includes mushrooms, molds and yeasts. Most fungi are aerobic (use oxygen), are found almost everywhere in extremely small quantities because of their spores, and are most commonly microscopically small. They consume organic matter, wherever humidity and temperature are sufficient, indoors or out. Toxins are enzymes or proteins.
Where conditions are right, fungi proliferate grow colonies and mycotoxin levels become high. Toxins vary greatly in their severity. Some fungi produce severe toxins only at specific levels of moisture, temperature or oxygen in the air. Some toxins are lethal, some cause identifiable diseases or health problems, some weaken the immune system without producing symptoms specific to that toxin, some act as allergens or irritants, and some have no known effect on the human organism. Some mycotoxins cause death more among the farm animal population than in humans. Some mycotoxins hurt other micro-organisms such as other fungi or even bacteria. See penicillin.
Mycotoxins appear in the food chain as a result of fungal infection of the crop. If an infected crop is not eaten by humans, the mycotoxin is still dangerous to human health, because the crop may be given as animal feed to farm animals. Mycotoxins greatly resist decomposition or being broken down in digestion, so they remain in the food chain in meat and dairy products. Even temperature treatments, such as cooking and freezing, do not destroy mycotoxins. For example Fusarium ear diseases in cereals, or the infection of stored products. Ethanol (ethyl alcohol or grain alcohol) is produced when some yeasts (e.g. Saccharomyces cerevisiae) consume sugars under low oxygen levels.
Buildings are another source of mycotoxins. Public concern over mycotoxins increased following multi-million dollar toxic mold settlements in the 1990s. The negative health effects of mycotoxins are a function of the concentration, the duration of exposure and the subject's sensitivities. The concentrations experienced in a normal home, office or school are often too low to trigger a health response in occupants.
Food-based mycotoxins have been studied extensively worldwide throughout the 20th century. 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.
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[edit] Major groups of food toxins
Aflatoxins are produced by Aspergillus species, and are largely associated with commodities produced in the tropics and sub-tropics, such as groundnuts, other edible nuts, figs, spices and maize. Aflatoxin 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 species which grows in warm humid conditions. Aspergillus ochraceus is found as a contaminant of a wide range of commodities including cereals and their products, fruit and a wide range of beverages and spices. Aspergillus carbonarius is the other main species associated in warm humid conditions found mainly on vine fruit and dried vine products particularly in the Mediterranean basin. It causes kidney damage in humans and is a potential carcinogen.
Patulin is associated with a range of fungal species and is found in moldy 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 diarrhea and potentially death.
[edit] Mycotoxin binding agents/Mycotoxin Deactivators
In the feed and food industry it had become common practice to add mycotoxin binding agents. To reverse the adverse effects of mycotoxins, the following criteria are used to evaluate the functionality of any binding additive:
- Efficacy of active component verified by scientific data
- A low effective inclusion rate
- Stability over a wide pH range
- High capacity to adsorb high concentrations of mycotoxins
- High affinity to adsorb low concentrations of mycotoxins interactions between toxins
- Affirmation of chemical interaction between mycotoxin and adsorbent
- Proven in-vivo data with all major mycotoxins
- Non toxic, environmentaly friendly component
Since not all mycotoxins can be bound to such agents, the latest approach to mycotoxin control is mycotoxin deactivation. By means of enzymes (esterase, expoxidase), yeast (Trichosporon mycotoxinvorans) or bacterial strains (Eubacterium BBSH 797), mycotoxins are detoxified to non-toxic metabolites.
[edit] Mycotoxins killing pets
Since the 1990s it has been widely acknowledged that pet food can also contain mycotoxins.[citation needed] [1]
[edit] Mycotoxins in fiction
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 for stealing from them by being administered a "Russian mycotoxin", which alters his nervous tissue and renders him unable to access cyberspace.
[edit] Control
- On farm management, rapid drying and good storage can effectively prevent mould growth in moisture.
- Rapid assay at sheller intake by TLC, immunoassay and HPLC.
- Sorting after shelling, discolored kernels (strains) usually contaminated.
In animal husbandry the use of mycotoxin deactivators and mycotoxin binders in feedstuffs has become common practice.
