Mycotoxin
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2008-06-15T16:36:00Z
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{{Cleanup|date=April 2007}}
{{toxicology}}
'''Mycotoxin''' (from the [[Ancient Greek|Greek]] μύκης (mykes, mukos) "fungus") is a [[toxin]] produced by an organism of the [[fungus]] kingdom, which includes [[mushrooms]], [[molds]] and [[yeasts]]. Most fungi are [[aerobic]] (use oxygen). Fungi are found almost everywhere in extremely small quantities because of their [[spores]], and are most commonly [[microscopic]]ally small. They consume [[Organic material|organic]] matter, wherever [[humidity]] and [[temperature]] are sufficient.
Where conditions are right, fungi [[proliferate]] into [[Colony (biology)|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 humans. Some mycotoxins generally have more negative impacts on farm animal populations than on humans. Some mycotoxins are harmful to other micro-organisms such as other fungi or even bacteria; [[penicillin]] is one example.
Mycotoxins can appear in the food chain as a result of [[fungal infection]] of [[agriculture|crop]]s, either by being eaten directly by humans, or by being used as livestock feed. 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.
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 were 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 [[European Commission|Commission]] regulations.
Various wild mushrooms also contain an assortment of mycotoxins that can cause noteworthy health problems for humans who eat wild mushrooms without first properly identifying the specimens as safe edibles, in such cases sometimes causing mild to catastrophic [[mushroom poisoning]]. The bulk of this article, however, is about mycotoxins that are found in fungi other than mushrooms.
== Major groups of food toxins ==
'''[[Aflatoxin]]s''' are produced by ''[[Aspergillus]]'' species, and are largely associated with [[commodities]] produced in the [[tropics]] and [[subtropics]], such as [[groundnuts]], other [[edible]] [[nut (fruit)|nuts]], [[figs]], [[spices]] and [[maize]]. Aflatoxin B<sub>1</sub>, the most [[toxic]], is a potent [[carcinogen]] and has been associated with [[Hepatocellular carcinoma|liver cancer]].
'''[[Ochratoxin|Ochratoxin A]]''' is produced by ''Penicillium verrucosum'', which is generally associated with [[temperate]] [[climates]], and ''Aspergillus'' species which grow 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 alcoholic [[fermentation (food)|fermentation]] and so is not found in [[Alcoholic beverage|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]]; and the '''[[trichothecenes]]''', including [[deoxynivalenol]], and '''[[zearalenone]]''', the last two of which are very stable and can survive [[cooking]]. The trichothecenes are [[Acute (medical)|acutely]] toxic to humans, causing sickness and diarrhea and potentially death.
[[Stachybotrys]] and [[Penicillium]]
== Mycotoxin binding agents and deactivators ==
In the feed and food industry it had become common practice to add mycotoxin binding agents such as [[Montmorillonite]] or [[bentonite]] clay. 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, environmentally 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]], [[epoxidase]]), [[yeast]] ([[Trichosporon mycotoxinvorans]]) or bacterial strains ([[Eubacterium]] BBSH 797), mycotoxins are detoxified to non-toxic metabolites.
==Mycotoxins killing humans ==
In 2004 in Kenya 125 people died and nearly 200 others were treated after eating [[aflatoxin]] contaminated maize. <ref name=Lewis_et_al> {{Citation
| last1 = Lewis | first1 = Lauren
| last2 = et al
| title = Aflatoxin Contamination of Commercial Maize Products during an Outbreak of Acute Aflatoxicosis in Eastern and Central Kenya
| journal = Environmental Health Perspectives
| volume = 113
| edition= 12
| year = 2005
| url = http://www.ehponline.org/docs/2005/7998/abstract.html
}}</ref>
The deaths were mainly associated with homegrown maize that had not been treated with fungicides or properly dried before storage. Due to food shortages at the time, farmers may have been harvesting maize earlier than normal to prevent thefts from their fields, so that the grain had not fully matured and was more susceptible to infection.
== Mycotoxins in pet food ==
There have been outbreaks of pet food containing mycotoxins in North America.<ref>{{cite web|url=http://www.news.cornell.edu/stories/Jan06/dogs.dying.ssl.html|title=Dogs keep dying: Too many owners remain unaware of toxic dog food|publisher=Cornell University Chronicle|author=Susan S. Lang|date=2006-01-06}}</ref>
== 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 war-time mycotoxin", which alters his nervous tissue and renders him unable to access cyberspace.
==References==
{{reflist}}
==See also==
*[[Mold]]
*[[Mold health issues]]
*[[Mold growth, assessment, and remediation]]
*[[Mushroom poisoning]]
==External links==
* [http://www.romerlabs.com/mycotoxins.html Detailed information about mycotoxins]
* [http://www.mycotoxins.info Information on mycotoxins for cereal farmers on mycotoxins contaminating fields, as well as information and news pertaining to plant producers, livestock farmers, feed millers, scientists, veterinarians and consumers]
* [http://www.knowmycotoxins.com Mycotoxins- how they are produced, impact on animals, issues with feed sampling and possible strategies to maintain animal health and performance]
* [http://www.fao.org/DOCREP/ARTICLE/AGRIPPA/556_EN.HTM Microbiology of Animal Feeds]
* [http://americanmushrooms.com/toxicms.htm Information on mycotoxins in wild mushrooms]
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