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{{traducción|ci=en|art=Mycotoxin}} |
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'''Micotoxina''' (del griego μύκης (mykes, mukos) “hongo”) es una [[toxina]] producida por un organismo del Reino [[Fungi]], que incluye setas, mohos y levaduras. La mayoría de los hongos son aeróbicos (uso de oxígeno), se encuentran casi por todas partes en cantidades pequeñas debido a sus esporas, y son comúnmente microscópicos. Dado que son organismos heterótrofos, deben consumir materia orgánica. Dondequiera que la humedad y la temperatura sean las adecuadas. Las micotoxinas poseen estructuras bioquímicas diversas: así pueden ser proteínas o no (como por ejemplo la [[penicilina]], la [[patulina]], [[aflatoxina]]...). |
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{{en obras}} |
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Las '''micotoxinas''' (del [[griego]] μύκης (''mykes, mukos''),«hongo» y el [[latín]] ''toxicum'' («veneno») es un metabolito tóxico producido por organismos del reino [[fungi]], que incluye setas, mohos y levaduras.<ref name=Turner09>{{cite journal |author=Turner NW, Subrahmanyam S, Piletsky SA |title=Analytical methods for determination of mycotoxins: a review |journal=Anal. Chim. Acta |volume=632 |issue=2 |pages=168–80 |year=2009 |pmid=19110091 |doi=10.1016/j.aca.2008.11.010 }}</ref><ref>{{cite journal |author=Richard JL |title=Some major mycotoxins and their mycotoxicoses—an overview |journal=Int. J. Food Microbiol. |volume=119 |issue=1–2 |pages=3–10 |year=2007 |pmid=17719115 |doi=10.1016/j.ijfoodmicro.2007.07.019 }}</ref> |
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El término suele referirse solo a las sustancias tóxicas producidas por hongos que se desarrollan en los productos agrícolas. <ref>{{cita web|url=http://www.univalle.edu/publicaciones/brujula/brujula18/pagina11.htm|apellido= Abecia Soria|nombre= Luis|título=Micotoxinas en los alimentos|fechaacceso=30 de septiembre de 2011}}</ref> La misma especie de hongo puede generar varias toxinas diferentes, a la vez que la misma toxina puede ser producida por varias especies.<ref>{{cite journal |author=Robbins CA, Swenson LJ, Nealley ML, Gots RE, Kelman BJ |title=Health effects of mycotoxins in indoor air: a critical review |journal=Appl Occup Environ Hyg |volume=15 |issue=10 |pages=773–84 |year=2000 |pmid=11036728 |doi=10.1080/10473220050129419 }}</ref> |
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==Overview== |
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Most fungi are [[Aerobic organism|aerobic]] (use oxygen) and are found almost everywhere in extremely small quantities due to the minute size of their [[spores]]. They consume [[Organic material|organic]] matter wherever [[humidity]] and [[temperature]] are sufficient. Where conditions are right, fungi [[cell growth|proliferate]] into [[Colony (biology)|colonies]] and mycotoxin levels become high. The reason for the production of mycotoxins is not yet known; they are necessary for neither growth nor the development of the fungi.<ref>{{cite journal |author=Fox EM, Howlett BJ |title=Secondary metabolism: regulation and role in fungal biology |journal=Curr. Opin. Microbiol. |volume=11 |issue=6 |pages=481–7 |year=2008 |pmid=18973828 |doi=10.1016/j.mib.2008.10.007 }}</ref> Because mycotoxins weaken the receiving host, the fungus may use them as a strategy to better the environment for further fungal proliferation. The production of toxins depends on the surrounding intrinsic and extrinsic environments and the toxins vary greatly in their severity, depending on the organism infected and its susceptibility, metabolism, and defense mechanisms.<ref>{{cite journal |author=Hussein HS, Brasel JM |title=Toxicity, metabolism, and impact of mycotoxins on humans and animals |journal=Toxicology |volume=167 |issue=2 |pages=101–34 |year=2001 |pmid=11567776 |doi=10.1016/S0300-483X(01)00471-1}}</ref> Some of the health effects found in animals and humans include death, identifiable diseases or health problems, weakened immune systems without specificity to a toxin, and as allergens or irritants. Some mycotoxins are harmful to other micro-organisms such as other fungi or even bacteria; [[penicillin]] is one example.<ref>{{cite journal |author=Keller NP, Turner G, Bennett JW |title=Fungal secondary metabolism – from biochemistry to genomics |journal=Nat. Rev. Microbiol. |volume=3 |issue=12 |pages=937–47 |year=2005 |pmid=16322742 |doi=10.1038/nrmicro1286 }}</ref> It has been suggested that mycotoxins in stored animal feed are the cause of of apparent sex change in hens.<ref>{{cite web|url=http://www.bbc.co.uk/news/uk-england-cambridgeshire-12906196|title='Sex-change' chicken shocks Cambridgeshire owner|publisher=BBC News|date=31 March 2011|accessdate=31 March 2011}}</ref> |
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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. |
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Although various wild mushrooms contain an assortment of poisons that are definitely fungal metabolites causing noteworthy health problems for humans, they are rather arbitrarily excluded from discussions of mycotoxicology. In such cases the distinction is based on the size of the producing fungus and human intention.<ref name=Bennett03>{{cite journal |author=Bennett JW, Klich M |title=Mycotoxins |journal=Clin. Microbiol. Rev. |volume=16 |issue=3 |pages=497–516 |year=2003 |pmid=12857779 |pmc=164220 |doi=10.1128/CMR.16.3.497-516.2003}}</ref> Mycotoxin exposure is almost always accidental whereas with mushrooms improper identification and ingestion causing [[mushroom poisoning]] is commonly the case. Ingestion of misidentified mushrooms containing mycotoxins may result in hallucinations. The cyclopeptide-produced ''[[Amanita phalloides|Amanita phalloide]]'' is well known for its toxic potential and is responsible for approximately 90% of all mushroom fatalities.<ref>{{cite journal |author=Berger KJ, Guss DA |title=Mycotoxins revisited: Part I |journal=J Emerg Med |volume=28 |issue=1 |pages=53–62 |year=2005 |pmid=15657006 |doi=10.1016/j.jemermed.2004.08.013 }}</ref> The other primary mycotoxin groups found in mushrooms include: orellanine, monomethylhydrazine, disulfiram-like, hallucinogenic indoles, muscarinic, isoxazole, and gastrointestinal (GI)-specific irritants.<ref>{{cite journal |author=Berger KJ, Guss DA |title=Mycotoxins revisited: Part II |journal=J Emerg Med |volume=28 |issue=2 |pages=175–83 |year=2005 |pmid=15707814 |doi=10.1016/j.jemermed.2004.08.019 }}</ref> The bulk of this article is about mycotoxins that are found in microfungi other than poisons from mushrooms or macroscopic fungi.<ref name=Bennett03/> |
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Many international agencies are trying to achieve universal standardization of regulatory limits for mycotoxins. Currently, over 100 countries have regulations regarding mycotoxins in the feed industry, in which 13 mycotoxins or groups of mycotoxins are of concern.<ref>{{cite journal |author=van Egmond HP, Schothorst RC, Jonker MA |title=Regulations relating to mycotoxins in food: perspectives in a global and European context |journal=Anal Bioanal Chem |volume=389 |issue=1 |pages=147–57 |year=2007 |pmid=17508207 |doi=10.1007/s00216-007-1317-9 }}</ref> The process of assessing a need for mycotoxin regulation includes a wide array of in-laboratory testing that includes extracting, clean-up and separation techniques.<ref name=Shephard08>{{cite journal |author=Shephard GS |title=Determination of mycotoxins in human foods |journal=Chem Soc Rev |volume=37 |issue=11 |pages=2468–77 |year=2008 |pmid=18949120 |doi=10.1039/b713084h }}</ref> Most official regulations and control methods are based on high-performance liquid techniques (e.g., [[High-performance liquid chromatography|HPLC]]) through international bodies.<ref name=Shephard08/> It is implied that any regulations regarding these toxins will be in co-ordinance with any other countries with which a trade agreement exists. Many of the standards for the method performance analysis for mycotoxins is set by the [[European Committee for Standardization]] (CEN).<ref name=Shephard08/> However, one must take note that scientific risk assessment is commonly influenced by culture and politics, which, in turn, will affect trade regulations of mycotoxins.<ref>{{cite journal |author=Kendra DF, Dyer RB |title=Opportunities for biotechnology and policy regarding mycotoxin issues in international trade |journal=Int. J. Food Microbiol. |volume=119 |issue=1–2 |pages=147–51 |year=2007 |pmid=17727996 |doi=10.1016/j.ijfoodmicro.2007.07.036 }}</ref> |
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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 [[Directive (European Union)|directives]] and [[European Commission|Commission]] regulations. The [[U.S. Food and Drug Administration]] has regulated and enforced limits on concentrations of mycotoxins in foods and feed industries since 1985. It is through various compliance programs that the FDA monitors these industries to guarantee that mycotoxins are kept at a practical level. These compliance programs sample food products including peanuts and peanut products, tree nuts, corn and corn products, cottonseed, and milk. There is still a lack of sufficient surveillance data on some mycotoxins that occur in the U.S., which is due largely to the lack of reliable analytical methods.<ref>{{cite journal |author=Wood GE |title=Mycotoxins in foods and feeds in the United States |journal=J. Anim. Sci. |volume=70 |issue=12 |pages=3941–9 |date=1 December 1992|pmid=1474031 }}</ref> |
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== Major groups == |
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'''[[Aflatoxin]]s''' are a type of mycotoxin produced by ''[[Aspergillus]]'' species of fungi, such as ''[[Aspergillus flavus|A. flavus]]'' and ''[[Aspergillus parasiticus|A. parasiticus]]''.<ref name=Martins01>{{cite journal |author=Martins ML, Martins HM, Bernardo F |title=Aflatoxins in spices marketed in Portugal |journal=Food Addit Contam |volume=18 |issue=4 |pages=315–9 |year=2001 |pmid=11339266 |doi=10.1080/02652030120041 }}</ref> The umbrella term aflatoxin refers to four different types of mycotoxins produced, which are B1, B2, G1, and G2.<ref name=Yin08>{{cite journal |author=Yin YN, Yan LY, Jiang JH, Ma ZH |title=Biological control of aflatoxin contamination of crops |journal=J Zhejiang Univ Sci B |volume=9 |issue=10 |pages=787–92 |year=2008 |pmid=18837105 |pmc=2565741 |doi=10.1631/jzus.B0860003 }}</ref> Aflatoxin B<sub>1</sub>, the most toxic, is a potent [[carcinogen]] and has been directly correlated to adverse health effects, such as [[Hepatocellular carcinoma|liver cancer]], in many animal species.<ref name=Martins01/> Aflatoxins are largely associated with [[commodities]] produced in the [[tropics]] and [[subtropics]], such as [[cotton]], [[peanuts]], [[spices]], [[pistachios]] and [[maize]].<ref name=Martins01/><ref name=Yin08/> |
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'''[[Ochratoxin]]''' is a mycotoxin that comes in three secondary metabolite forms, A, B, and C. All are produced by ''Penicillium'' and ''Aspergillus'' species. The three forms differ in that Ochratoxin B (OTB) is a nonchlorinated form of Ochratoxin A (OTA) and that Ochratoxin C (OTC) is an ethyl ester form Ochatoxin A.<ref name=Bayman06>{{cite journal |author=Bayman P, Baker JL |title=Ochratoxins: a global perspective |journal=Mycopathologia |volume=162 |issue=3 |pages=215–23 |year=2006 |pmid=16944288 |doi=10.1007/s11046-006-0055-4 }}</ref> ''Aspergillus ochraceus'' is found as a [[contaminant]] of a wide range of commodities including [[beverages]] such as beer and wine. ''Aspergillus carbonarius'' is the main species found on vine fruit, which releases its toxin during the juice making process.<ref name=Mateo07>{{cite journal |author=Mateo R, Medina A, Mateo EM, Mateo F, Jiménez M |title=An overview of ochratoxin A in beer and wine |journal=Int. J. Food Microbiol. |volume=119 |issue=1–2 |pages=79–83 |year=2007 |pmid=17716764 |doi=10.1016/j.ijfoodmicro.2007.07.029 }}</ref> OTA has been labeled as a carcinogen and a nephrotoxin, and has been linked to tumors in the human urinary tract, although research in humans is limited by [[confounding|confounding factors]].<ref name=Bayman06/><ref name=Mateo07/> |
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'''[[Citrinin]]''' is a toxin that was first isolated from ''Penicillium citrinum'', but has been identified in over a dozen species of ''Penicillium'' and several species of ''[[Aspergillus]]''. Some of these species are used to produce human foodstuffs such as cheese (''Penicillium camemberti''), sake, [[miso]], and [[soy sauce]] (''[[Aspergillus oryzae]]''). Citrinin is associated with yellow rice disease in Japan and acts as a [[nephrotoxin]] in all animal species tested. Although it is associated with many human foods ([[wheat]], [[rice]], [[maize|corn]], [[barley]], [[oats]], [[rye]], and food colored with [[Monascus]] pigment) its full significance for human health is unknown. Citrinin can also act synergistically with Ochratoxin A to depress [[RNA synthesis]] in murine kidneys.<ref name=Bennett03/> |
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'''[[Ergot]] Alkaloids''' are compounds produced as a toxic mixture of alkaloids in the [[sclerotium|sclerotia]] of species of ''Claviceps'', which are common pathogens of various grass species. The ingestion of ergot sclerotia from infected cereals, commonly in the form of bread produced from contaminated flour, cause [[ergotism]] the human disease historically known as St. Anthony’s Fire. There are two forms of ergotism gangrenous affecting blood supply to extremities and convulsive that affect the [[central nervous system]]. Modern methods of grain cleaning have significantly reduced ergotism as a human disease, however it is still an important veterinarian problem. Ergot alkaloids have been used pharmaceutically.<ref name=Bennett03/> |
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'''[[Patulin]]''' is a toxin produced by the ''[[Penicillium expansum|P. expansum]]'', ''Aspergillus'', ''Penicillium'', and ''[[Paecilomyces]]'' fungal species. ''P. expansum'' is especially associated with a range of moldy [[fruit]]s and [[vegetable]]s, in particular rotting apples and figs.<ref name=Moss08>{{cite journal |author=Moss MO |title=Fungi, quality and safety issues in fresh fruits and vegetables |journal=J. Appl. Microbiol. |volume=104 |issue=5 |pages=1239–43 |year=2008 |pmid=18217939 |doi=10.1111/j.1365-2672.2007.03705.x }}</ref><ref name=Trucksess08>{{cite journal |author=Trucksess MW, Scott PM |title=Mycotoxins in botanicals and dried fruits: A review |journal=Food Addit Contam. |volume=25 |issue=2 |pages=181–92 |year=2008 |pmid=18286408 |doi=10.1080/02652030701567459}}</ref> It is destroyed by the [[fermentation (food)|fermentation]] process and so is not found in apple beverages, such as [[cider]]. Although patulin has not been shown to be carcinogenic, it has been reported to damage the [[immune system]] in animals.<ref name=Moss08/> In 2004, the [[European Community]] set limits to the concentrations of patulin in food products. They currently stand at 50 μg/kg in all fruit juice concentrations, at 25 μg/kg in solid apple products used for direct consumption, and at 10 μg/kg for children's apple products, including apple juice.<ref name=Moss08/><ref name=Trucksess08/> |
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'''[[Fusarium]]''' toxins are produced by over 50 species of ''Fusarium'' and have a history of infecting the grain of developing cereals such as [[wheat]] and [[maize]].<ref>{{cite journal |author=Cornely OA |title=''Aspergillus'' to Zygomycetes: causes, risk factors, prevention, and treatment of invasive fungal infections |journal=Infection |volume=36 |issue=4 |pages=296–313 |year=2008 |pmid=18642109 |doi=10.1007/s15010-008-7357-z }}</ref><ref>{{cite journal |author=Schaafsma AW, Hooker DC |title=Climatic models to predict occurrence of Fusarium toxins in wheat and maize |journal=Int. J. Food Microbiol. |volume=119 |issue=1–2 |pages=116–25 |year=2007 |pmid=17900733 |doi=10.1016/j.ijfoodmicro.2007.08.006 }}</ref> They include a range of mycotoxins, such as: the '''[[fumonisins]]''', which affect the nervous systems of [[horse]]s and may cause cancer in [[rodent]]s; the '''[[trichothecenes]]''', which are most strongly associated with chronic and fatal toxic effects in animals and humans; and '''[[zearalenone]]''', which is not correlated to any fatal toxic effects in animals or humans. Some of the other major types of ''Fusarium'' toxins include: beauvercin and enniatins, [[butenolide]], equisetin, and fusarins.<ref>{{cite journal |author=Desjardins AE, Proctor RH |title=Molecular biology of ''Fusarium'' mycotoxins |journal=Int. J. Food Microbiol. |volume=119 |issue=1–2 |pages=47–50 |year=2007 |pmid=17707105 |doi=10.1016/j.ijfoodmicro.2007.07.024 }}</ref> |
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== Binding agents and deactivators == |
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In the feed and food industry it has become common practice to add mycotoxin binding agents such as [[Montmorillonite]] or [[bentonite]] clay in order to affectively adsorb the mycotoxins.<ref name=Kabak06>{{cite journal |author=Kabak B, Dobson AD, Var I |title=Strategies to prevent mycotoxin contamination of food and animal feed: a review |journal=Crit Rev Food Sci Nutr |volume=46 |issue=8 |pages=593–619 |year=2006 |pmid=17092826 |doi=10.1080/10408390500436185 }}</ref> To reverse the adverse effects of mycotoxins, the following criteria are used to evaluate the functionality of any binding additive: |
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* Efficacy of active component verified by scientific data |
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* A low effective inclusion rate |
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* Stability over a wide pH range |
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* High capacity to adsorb high concentrations of mycotoxins |
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* High affinity to adsorb low concentrations of mycotoxins |
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* Affirmation of chemical interaction between mycotoxin and adsorbent |
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* Proven ''in vivo'' data with all major mycotoxins |
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* Non-toxic, environmentally friendly component |
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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 can be reduced during pre-harvesting contamination. Other removal methods include physical separation, washing, milling, heat-treatment, radiation, extraction with solvents, and the use of chemical or biological agents. Irradiation methods have proven to be effective treatment against mold growth and toxin production.<ref name=Kabak06/> |
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==In the indoor environment== |
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Buildings are another source of mycotoxins and people living or working in areas with mold increase their chances of adverse health effects. Molds growing in buildings can be divided into three groups — Primary, Secondary, and Tertiary colonizers. Each group is categorized by the ability to grow at a certain water activity requirement. It has become difficult to identify mycotoxins production by indoor molds for many variables, such as (i) they may be masked as derivatives (ii) they are poorly documented and (iii) the fact that they are likely to produce different metabolites on building materials. Some of the mycotoxins in the indoor environment are produced by [[Alternaria]], [[Aspergillus]] (multiple forms), [[Penicillium]], and [[Stachybotrys]].<ref name= "Mycotoxin production by indoor molds.">{{cite journal|pmid=12781669|year=2003|last1=Fog Nielsen|first1=K|title=Mycotoxin production by indoor molds|volume=39|issue=2|pages=103–17|journal=Fungal genetics and biology : FG & B|doi=10.1016/S1087-1845(03)00026-4}}</ref> Stachybotrys chartarum contains a higher number of mycotoxins than other molds grown in the indoor environment and has been associated with allergies and respiratory inflammation.<ref name=Pestka08>{{cite journal |author=Pestka JJ, Yike I, Dearborn DG, Ward MD, Harkema JR |title=''Stachybotrys chartarum'', trichothecene mycotoxins, and damp building-related illness: new insights into a public health enigma |journal=Toxicol. Sci. |volume=104 |issue=1 |pages=4–26 |year=2008 |pmid=18007011 |doi=10.1093/toxsci/kfm284 }}</ref> The infestation of S. chartarum in buildings containing gypsum board, as well as on ceiling tiles, is very common and has recently become a more recognized problem. When gypsum board has been repeatedly introduced to moisture S. chartarum grows readily on its cellulose face.<ref name=Godish01>{{cite book |author=Godish, Thad |title=Indoor environmental quality |publisher=Lewis Publishers |location=Chelsea, Mich |year=2001 |pages=183–4 |isbn=1-56670-402-2 }}</ref> This stresses the importance of moisture controls and ventilation within residential homes and other buildings. 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. |
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In the 1990s, public concern over mycotoxins increased following multi-million dollar [[toxic mold]] settlements. The lawsuits took place after the [[Centers for Disease Control and Prevention|Center for Disease Control]] (CDC) did a study in Cleveland Ohio and claimed that there was an association between mycotoxins from ''Stachybotrys'' spores and pulmonary hemorrhage in infants. However in 2000, based on internal and external reviews of their data, the CDC concluded that because of flaws in their methods the association was not proven. ''Stachybotrys'' spores in animal studies have been shown to cause lung hemorrhaging but only at very high concentrations.<ref>{{cite journal |author= |title=Update: Pulmonary hemorrhage/hemosiderosis among infants—Cleveland, Ohio, 1993–1996 |journal=MMWR Morb. Mortal. Wkly. Rep. |volume=49 |issue=9 |pages=180–4 |year=2000 |pmid=11795499 |url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4909a3.htm |author1= Centers for Disease Control and Prevention (CDC) }}</ref> |
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One study by the Center of Integrative Toxicology at Michigan State University investigated the causes of Damp Building Related Illness (DBRI). They found that ''Stachybotrys'' is possibly an important contributing factor to DBRI. So far animal models indicate that airway exposure to ''S. chartarum '' can evoke allergic sensitization, inflammation, and cytotoxicity in the upper and lower respiratory tracts. Trichothecene toxicity appears to be an underlying cause of many these adverse effects. Recent findings indicate that lower doses (studies usually involve high doses) can cause these symptoms.<ref name=Pestka08/> |
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Some toxicologists have used the Concentration of No Toxicological Concern (CoNTC) measure to represent the airborne concentration of mycotoxins that are expected to cause no hazard to humans (exposed continuously throughout a 70–yr lifetime). The resulting data of several studies have thus far demonstrated that common exposures to airborne mycotoxins in the built indoor environment are below the CoNTC, however agricultural environments have potential to produce levels greater than the CoNTC.<ref>{{cite journal |author=Hardin BD, Robbins CA, Fallah P, Kelman BJ |title=The concentration of no toxicologic concern (CoNTC) and airborne mycotoxins |journal=J. Toxicol. Environ. Health Part A |volume=72 |issue=9 |pages=585–98 |year=2009 |pmid=19296408 |doi=10.1080/15287390802706389 |url=http://www.informaworld.com/10.1080/15287390802706389}}</ref> |
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==Human health effects == |
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Mycotoxicoses is the term used for poisoning associated with exposures to mycotoxins. The symptoms of a mycotoxicosis depend on the type of mycotoxin; the concentration and length of exposure; as well as age, health, and sex of the exposed individual.<ref name=Bennett03/> The synergistic effects associated with several other factors such as genetics, diet, and interactions with other toxics have been poorly studied. Therefore it is possible that vitamin deficiency, caloric deprivation, alcohol abuse, and infectious disease status can all have compounded effects with mycotoxins.<ref name=Bennett03/> In turn, mycotoxins have the potential for both acute and chronic health effects via ingestion, skin contact, and inhalation. These toxins can enter the blood stream and lymphatic system, they inhibit protein synthesis, damage [[macrophage]] systems, inhibit particle clearance of the lung, and increase sensitivity to bacterial endotoxin.<ref name=Godish01/> |
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Notably Severe Cases of Aflatoxin Ingestion: |
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In 2004 in Kenya 125 people died and nearly 200 others were treated after eating [[aflatoxin]] contaminated maize.<ref>{{cite journal |author=Lewis L, Onsongo M, Njapau H, ''et al.'' |title=Aflatoxin contamination of commercial maize products during an outbreak of acute aflatoxicosis in eastern and central Kenya |journal=Environ. Health Perspect. |volume=113 |issue=12 |pages=1763–7 |year=2005 |pmid=16330360 |pmc=1314917 |doi=10.1289/ehp.7998 |url=http://ehpnet1.niehs.nih.gov/members/2005/7998/7998.html}}</ref> |
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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. |
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== In pet food == |
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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> |
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== In fiction == |
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A fictional use of a mycotoxin occurs in [[William Gibson]]'s seminal novel ''[[Neuromancer]].'' A "Russian war-time mycotoxin" is administered to Case, the novel's protagonist. |
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==See also== |
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{{commons category|mycotoxins}} |
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*[[Mold]] |
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*[[Mold health issues]] |
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*[[Mold growth, assessment, and remediation]] |
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*[[Mushroom poisoning]] |
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==References== |
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{{Reflist|2}} |
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==External links== |
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{{wiktionary|mycotoxin}} |
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* [http://www.aspergillus.org.uk/secure/metabolites/list_by_secmet.php?toxin=y Detailed listing and information on all ''Aspergillus'' mycotoxins] |
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* [http://www.fao.org/DOCREP/ARTICLE/AGRIPPA/556_EN.HTM Microbiology of Animal Feeds] |
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{{Toxins}} |
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[[Category:Mycotoxins| ]] |
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Donde las condiciones son propicias, los hongos proliferan, formando colonias, y los niveles de micotoxina pueden llegar a ser altos. Las micotoxinas varían grandemente en su peligrosidad. Algunos hongos producen solamente toxinas severas en niveles específicos de humedad, de temperatura o de oxígeno en el aire. Otras son mortales, causan enfermedades o problemas de salud identificables, algunas debilitan el sistema inmune sin producir síntomas específicos, actúan como los alergénicos o irritantes, y otras no tienen ningún efecto conocido en el organismo humano. Algunas micotoxinas causan la muerte de animales del campo. La función de las micotoxinas proteger al organismo que las produce ante otros que pueden, si no matarlo, impedir su máximo desarrollo y crecimiento generando competencias. En este sentido, Fleming descubrió la penicilina como consecuencia de que los hongos que estaba cultivando en las placas de Petri inhibieron el crecimiento de bacterias a su alrededor. |
Donde las condiciones son propicias, los hongos proliferan, formando colonias, y los niveles de micotoxina pueden llegar a ser altos. Las micotoxinas varían grandemente en su peligrosidad. Algunos hongos producen solamente toxinas severas en niveles específicos de humedad, de temperatura o de oxígeno en el aire. Otras son mortales, causan enfermedades o problemas de salud identificables, algunas debilitan el sistema inmune sin producir síntomas específicos, actúan como los alergénicos o irritantes, y otras no tienen ningún efecto conocido en el organismo humano. Algunas micotoxinas causan la muerte de animales del campo. La función de las micotoxinas proteger al organismo que las produce ante otros que pueden, si no matarlo, impedir su máximo desarrollo y crecimiento generando competencias. En este sentido, Fleming descubrió la penicilina como consecuencia de que los hongos que estaba cultivando en las placas de Petri inhibieron el crecimiento de bacterias a su alrededor. |
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== Referencias == |
== Referencias == |
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* Okeke, B. et al; 1993; Identification of mycotoxin-producin fungal strains: a step in the isolation of compounds active against rice fungan diseases; J. Agric. Food Chem. 41:1731-1735 |
* Okeke, B. et al; 1993; Identification of mycotoxin-producin fungal strains: a step in the isolation of compounds active against rice fungan diseases; J. Agric. Food Chem. 41:1731-1735 |
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* Carrillo, L.; Mohos y micotoxinas; http://www.unsa.edu.ar/matbib/hongos/01htextomohos.pdf (visitado 25-12-2006). |
* Carrillo, L.; Mohos y micotoxinas; http://www.unsa.edu.ar/matbib/hongos/01htextomohos.pdf (visitado 25-12-2006). |
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[[Categoría:Fungi]] |
[[Categoría:Fungi]] |
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Revisión del 05:40 1 oct 2011
Las micotoxinas (del griego μύκης (mykes, mukos),«hongo» y el latín toxicum («veneno») es un metabolito tóxico producido por organismos del reino fungi, que incluye setas, mohos y levaduras.[1][2]
El término suele referirse solo a las sustancias tóxicas producidas por hongos que se desarrollan en los productos agrícolas. [3] La misma especie de hongo puede generar varias toxinas diferentes, a la vez que la misma toxina puede ser producida por varias especies.[4]
Donde las condiciones son propicias, los hongos proliferan, formando colonias, y los niveles de micotoxina pueden llegar a ser altos. Las micotoxinas varían grandemente en su peligrosidad. Algunos hongos producen solamente toxinas severas en niveles específicos de humedad, de temperatura o de oxígeno en el aire. Otras son mortales, causan enfermedades o problemas de salud identificables, algunas debilitan el sistema inmune sin producir síntomas específicos, actúan como los alergénicos o irritantes, y otras no tienen ningún efecto conocido en el organismo humano. Algunas micotoxinas causan la muerte de animales del campo. La función de las micotoxinas proteger al organismo que las produce ante otros que pueden, si no matarlo, impedir su máximo desarrollo y crecimiento generando competencias. En este sentido, Fleming descubrió la penicilina como consecuencia de que los hongos que estaba cultivando en las placas de Petri inhibieron el crecimiento de bacterias a su alrededor.
Los hongos que crecen sobre los vegetales no sólo son responsables del deterioro de los mismos, sino que también producen una serie de metabolitos que actúan como antibióticos frente a otros organismos que vayan a ocupar ese nicho ecológico y que en determinadas ocasiones pueden llegar a ser ingeridos por los seres humanos, ya sea directamenteo bien porque las ingerimos con otros alimentos como carnes, leche o derivados. Las micotoxinas, son compuestos ubicuos que difieren mucho en sus propiedades químicas, biológicas y toxicológicas Lo que implica que el problema de las micotoxicosis comienza en el campo y continúa durante toda la cadena de transformación-comercialización que acaba en la mesa del consumidor. Por lo tanto, la contaminación de la fruta por hongos causa no sólo altas pérdidas después de la recolección sino que también constituye una fuente de sustancias tóxicas y peligrosas para el ser humano (Bhatnagar et al.; 1992). Unas pocas micotoxinas se han comprobado en brotes de intoxicación animal y humana, y otras muchas se han ensayado en animales de experimentación. Se denomina micotoxicosis primaria a la que se produce al consumir vegetales contaminados, y secundaria a aquella que se produce al ingerir carne o leche de animales que comieron pastos o piensos con micotoxinas Las micotoxinas son sustancias muy específicas. Cuanto más compleja es la ruta biosintética de estos metabolitos secundarios, más restringido es el número de especies de hongos productores. Por ejemplo: las esporidesminas son formadas solamente por Pithomyces chartarum. La aflatoxina B1 es generada por tres especies estrechamente relacionadas Aspergillus flavus, Aspergillus nomius y Aspergillus parasiticus. (Carrillo, L.). Muchas veces la presencia de varias micotoxinas en conjunto, impiden el aislamiento de antibióticos o compuestos agrofarmacológicos útilies. (Okeke, 1993)
Las micotoxinas aparecen en la cadena de alimentos como resultado de la infección fúngica de la cosecha. Si una cosecha infectada no es comida por los seres humanos, la micotoxina sigue siendo peligrosa para la salud humana, porque la cosecha puede ser dada como alimento a los animales de granja. Las micotoxinas resisten la descomposición o no son inutilizadas durante la digestión, así que permanecen en la cadena de alimentos en carnes y productos lácteos. Incluso los tratamientos de temperatura, tales como cocinar y congelar, no destruyen todas las micotoxinas. Por ejemplo enfermedades del oidium (también se llama oidio) de Fusarium ssp en cereales, o la infección de productos almacenados.
Los edificios son otra fuente de micotoxinas.
Los efectos negativos de salud de micotoxinas son una función de concentración, duración de la exposición y las sensibilidades del sujeto. Las concentraciones experimentadas en un hogar, una oficina o una escuela normal son a menudo demasiado bajas para accionar una respuesta de la salud en inquilinos.
Los alimentos que poseen micotoxinas se han estudiado ampliamente por todo el mundo durante todo el siglo XX. En Europa, los niveles de una amplia gama de micotoxinas permitidas en la alimenteación y comida animal son fijados por una serie de directivas europeas y Comisión de regulaciones.
Referencias
- ↑ Turner NW, Subrahmanyam S, Piletsky SA (2009). «Analytical methods for determination of mycotoxins: a review». Anal. Chim. Acta 632 (2): 168-80. PMID 19110091. doi:10.1016/j.aca.2008.11.010.
- ↑ Richard JL (2007). «Some major mycotoxins and their mycotoxicoses—an overview». Int. J. Food Microbiol. 119 (1–2): 3-10. PMID 17719115. doi:10.1016/j.ijfoodmicro.2007.07.019.
- ↑ Abecia Soria, Luis. «Micotoxinas en los alimentos». Consultado el 30 de septiembre de 2011.
- ↑ Robbins CA, Swenson LJ, Nealley ML, Gots RE, Kelman BJ (2000). «Health effects of mycotoxins in indoor air: a critical review». Appl Occup Environ Hyg 15 (10): 773-84. PMID 11036728. doi:10.1080/10473220050129419.
- Okeke, B. et al; 1993; Identification of mycotoxin-producin fungal strains: a step in the isolation of compounds active against rice fungan diseases; J. Agric. Food Chem. 41:1731-1735
- Carrillo, L.; Mohos y micotoxinas; http://www.unsa.edu.ar/matbib/hongos/01htextomohos.pdf (visitado 25-12-2006).