Mycotoxin

Mold growth in barley

Mycotoxins (mold toxins) are secondary metabolic products from mold , which in vertebrates can be toxic even in the smallest quantities. In contrast to this, the toxic ingredients of large mushrooms are called mushroom poisons . A disease caused by mycotoxins is called mycotoxicosis .

discovery

Mold-infested foods and thus mycotoxins have been consumed since time immemorial. Serious thought was given to it for the first time since 1960, when thousands of turkeys in England died of moldy peanut meal. The intensive search for the toxic substances then led to the discovery of the aflatoxins . During the Second World War, a disease occurred in the USSR that inhibited the formation of white blood cells and was based on moldy millet and moldy wheat. Only after years, the disease-causing mycotoxin, which was T-2 toxin from the group of from Fusarium formed trichothecenes discovered that occurred in Russian grain samples having a concentration of up to 2.5%.

Occurrence

About 200 different toxins are now known, which are produced by over 300 types of fungus, whereby the production of a certain toxin can be limited to a few certain types, but can also be achieved by many types of several genera. The optimal conditions for the formation of the toxin and the growth of the mold need not necessarily match. Most mycotoxins are very resistant to heat and acid treatment.

The formation of mycotoxins is subject to pronounced regional and seasonal fluctuations and depends on the food available, water content in the substrate and surrounding air (humidity), temperature, pH value and interactions with other fungi. Substrates rich in carbohydrates of complex composition are preferred for poison formation .

Human beings are mainly threatened by contamination in food. All moldy foods can contain mycotoxins.

• Primary contamination: Grain was already attacked by mold in the field (e.g. ergot on rye , wheat , barley )
• Secondary contamination: stored food becomes moldy (e.g. Aspergillus or Penicillium spp.)
• Carry over : farm animals ingest moldy feed (e.g. maize, wheat, soy, palm kernel expeller) and pass on the toxins it contains to the products: milk , eggs , meat

The FAO estimates that around 25% of world food production contains mycotoxins. Grains (especially maize and wheat ) are most frequently contaminated with Fusarium toxins . Agricultural products from tropical and subtropical areas are often affected by aflatoxin infestation, as the Aspergillus flavus fungus only grows well from temperatures of 25 to 40 ° C. Mainly maize and oil-containing seeds and nuts , such as. B. Pistachios , peanuts , almonds and Brazil nuts .

effect

Mycotoxins can have toxic effects in humans and animals even in low concentrations.

In particular, mycotoxins

• carcinogenic ( carcinogenic effect)
• damage the central nervous system (have a neurotoxic effect)
• damage the immune system (have an immunosuppressive effect)
• damage the genetic material ( mutagenic )
• damage the womb ( teratogenic effect)
• Cause organ damage (e.g. liver or kidney ) (have a hepatotoxic or nephrotoxic effect)
• on contact cause skin and mucous membrane damage (from skin irritation to necrosis )
• Inhibit or initiate enzymatic metabolic processes
• allergic reactions trigger
• cause fertility disorders through hormonal effects .

A number of mycotoxins have the ability to prevent bacteria from multiplying. One speaks here of an antibiotic effect and uses this property in various drugs against bacterial infections . See also: penicillin .

species

Mycotoxins can be grouped together either because of a similar molecular structure or according to the type of mold that produces them:

• Aflatoxins
• Alternaria toxins such as B. Alternariol (AOH), Alternariol monomethylether (AME), Altenuen and tenuazonic acid
• Fusarium toxins such as trichothecenes (e.g. deoxynivalenol (DON), nivalenol, T-2 toxin), zearalenones, and fumonisins
• Ergot alkaloids (ergot alkaloids)
• Ochratoxins

Strictly speaking, ergot alkaloids should be counted among the fungus poisons . Because the producer, ergot (Claviceps purpurea), belongs to the large mushrooms, since small but clearly recognizable fruiting bodies grow out of the sclerotium in spring .

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  Salami with harmful mold

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  Bread with mold

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  Ears of rye with ergot

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  Rye contaminated with ergot

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  Mold growth on nectarines

List of mycotoxins (selection)

Name of the toxin (s)	Main producers	essential Occurrence	(Poison) effect
Aflatoxins	Aspergillus flavus Aspergillus parasiticus	Peanuts, cereals, corn, figs, milk ( carry over ) Contaminated rooms (via skin contact and respiratory tract)	hepatotoxic , carcinogenic , acute toxicity , aflatoxin B 1 = strongest mycotic carcinogen
Altenuen	Alternaria alternata Alternaria solani
Alternariol (AOH)	Alternaria alternata Alternaria solani	Fruits, vegetables, tobacco, millet, nuts	mutagenic
Alternariol monomethyl ether (AME)	Alternaria alternata Alternaria solani	Fruits, vegetables, tobacco, millet, nuts	mutagenic
Cephalosporin	Cephalosporium acremonium		antibiotic
Chaetomin	Chaetomium species		nephrotoxic , antibiotic effect on gram-positive bacteria
Citrinine	Aspergillus ochraceus Penicillium citrinum	Grain	hepatotoxic, nephrotoxic, carcinogenic
Deoxynivalenol (DON)	Fusarium culmorum Fusarium graminearum	Grain	gastrointestinal irritant
Fumagillin	Aspergillus fumigatus		inhibits angiogenesis , antibiotic
Fumonisins	Fusarium verticillioides Fusarium proliferatum Fusarium anthophilum	mainly corn	possibly carcinogenic, teratogenic
Fusarin C.	Fusarium species		mutagenic, presumably carcinogenic
Fusaric acid (FA)	Fusarium species		slightly toxic, antibiotic
Gliotoxin	Aspergillus fumigatus Aspergillus terreus Eurotium chevalieri Gliocladium fimbriatum		cytotoxic , immunosuppressive
Griseofulvin	Penicillium griseofulvum		antibiotic
Kojic acid	Aspergillus and Penicillium species	Corn, probably many other foods and feeds	weakly mutagenic, moderately antibiotic, epilepsy-like symptoms in animal experiments ( ip )
Moniliformin	Fusarium avenaceum Fusarium tricinctum Fusarium fusaroides Fusarium moniliforme	Barley, corn	gastroenteritic, hemorrhagic
Ergot alkaloids	Claviceps purpurea	Grain	ergotism
Mycophenolic acid	Penicillium brevicompactum
Nivalenol	Fusarium culmorum	Barley, corn, wheat	hemorrhagic
Ochratoxin A (OTA)	Aspergillus ochraceus Penicillium viridicatum	Peanuts, corn, wheat, cottonseed meal	nephrotoxic, dermatotoxic , carcinogenic
Patulin	Penicillium claviforme Penicillium expansum Penicillium griseofulvum Penicillium leucopus Penicillium clavatus Penicillium giganteus Penicillium terreus	Apple juice, apples and other types of fruit	hemorrhagic, edematous , carcinogenic in animal experiments ( sc. )
penicillin	Penicillium notatum		antibiotic
Penicillic acid	many species of Penicillium and Aspergillus	Corn, feed	antibiotic, carcinogenic in animal experiments (sc.)
Penitrem A	Penicillium carneum Penicillium crustosum	Meat, meat products	neurotoxic , tremorous
Roquefortine	Penicillium roqueforti Penicillium commune	Rice flour u. a. food	neurotoxic, paralytic
Satratoxins	Stachybotrys chartarum		systemic symptoms of intoxication
Sterigmatocystin	Aspergillus aurantiobrunneus Aspergillus nidulans Aspergillus quadrilineatus Aspergillus ustus Aspergillus variecolor Aspergillus versicolor	Hard cheese, green coffee beans, barley, corn, wheat, rice	carcinogenic, hepatotoxic, nephrotoxic
Tenuazonic acid	Alternaria alternata	Apples, tomatoes	antibiotic, antiviral, low toxicity, inhibits protein biosynthesis
Trichothecenes	mainly Fusarium species, also Cephalosporium , Stachybotrys , Trichoderma	Grain, contaminated areas (via skin contact and respiratory tract)	diverse
T-2 toxin	Fusarium culmorum Fusarium incarnatum Fusarium poae Fusarium solani Fusarium sporotrichioides Fusarium tricinctum Trichoderma lignorum	Barley, millet, corn, Contaminated rooms (via skin contact and respiratory tract)	dermatotoxic
Viomellein	Aspergillus ochraceus Penicillium cyclopium Penicillium melanoconidium Penicillium freii Penicillium viridicatum		Nephro- and hepatotoxic
Verrucosidine	Penicillium aurantiogriseum Penicillium melanoconidium Penicillium polonicum		neurotoxic
Verruculogen	Penicillium verrucosum Aspergillus fumigatus	Grain	tremorgenous, presumably tumor-promoting effect
Xanthomegnin	Aspergillus species Penicillium species Trichophyton species Microsporum species	Meat, meat products	hepatotoxic
Zearalenone (ZEA)	Fusarium avenaceum Fusarium culmorum Fusarium equiseti Fusarium gibbosum Fusarium lateritium Fusarium moniliform Fusarium nivale Fusarium oxysporum Fusarium graminearum Fusarium sambucinum Fusarium tricinctum	Cornflakes, barley, oats, millet, corn, nuts, rye, sesame flour, wheat	Effects as estrogen , infertility

Ethanol (ethyl alcohol), which is produced during the anaerobic metabolism of sugars by some yeasts (especially Saccharomyces cerevisiae ), is one of the primary metabolic products and is therefore not a mycotoxin in the narrower sense.

Detection methods

There are several physico-chemical methods for mycotoxin analysis:

• Thin layer chromatography (TLC)
• High performance liquid chromatography (HPLC)
• Gas chromatography (GC)
• Coupling of HPLC and GC with mass spectrometers
• Fluorescence polarization (FP)

During these examinations, the substances are extracted from the examination material with organic solvents and cleaned and concentrated in a complex process to such an extent that clear detection without interfering substances is possible. The HPLC / MS and GC / MS couplings enable both the reliable identification and quantification of the various mycotoxins. As a rule, derivatives (e.g. trimethylsilyl derivatives) are used for gas chromatography. When using the HPLC / MS coupling, underivatized mycotoxins can also be measured. Both electron impact ionization (EI) and chemical ionization (CI) with quadrupole and ion trap mass spectrometers are possible ionization methods. There are immunological ELISA methods and mycotoxin strip tests ("dipsticks"), which are carried out using the method of "capillary diffusion tests" or "flow-through tests", for rapid analysis of raw material acceptance in food and feed companies (especially for DON and ZEA) work. Recently there are also homogeneous Rapid Kinetic Assays, which as precision rapid tests enable precise quantitative determinations in less than 15 minutes.

Maximum volume regulations

EU-wide, the Commission Regulation (EC) No. 1881/2006 on the setting of maximum levels for certain contaminants in food of December 19, 2006 applies. In Switzerland, the maximum levels are determined by the EDI Ordinance on Maximum Levels for Contaminants (Contaminants Ordinance , VHK).

literature

• Frank Frössel: Mold in apartments. When the mushroom lives to sublet . Baulino Verlag, Waldshut-Tiengen 2006, ISBN 3-938537-18-3 .
• Lutz Roth, Hanns K. Frank, Kurt Kormann: Poison mushrooms · Mushroom poisons. Molds Mycotoxins. Occurrence, ingredients, fungal allergies. ecomed, Landsberg 1990, ISBN 3-609-64730-2 .
• Rudolf Weber: Mycotoxins in Food. In: Chemistry in Our Time. 17th year 1983, No. 5, pp. 146-151, ISSN  0009-2851 .
• Rolf Steinmüller: Mycotoxins and their rapid detection. Part 1. In: Mill + compound feed. 150th year 2013, issue 11, pp. 343-349, ISSN  0027-2949 .

Web links

Wiktionary: Mycotoxin  - explanations of meanings, word origins, synonyms, translations

• Information on the most important mycotoxins and their detection methods
• Information on the subject of mycotoxins for grain farmers, cattle farmers, feed mills, scientists, veterinarians and consumers (English)
• Homepage of the Society for Mycotoxin Research (English)
• Maximum amount regulations for mycotoxins in food in the European Union (EU) and in Germany - information from the Bavarian State Office for Health and Food Safety
• Mycotoxins - Information from the consumer portal VIS Bayern
• Toxic fungi - mycotoxins in food - information from the Federal Food Safety and Veterinary Office
• Mycotoxins - information from Agroscope

Individual evidence

1. ↑ Habermehl: The importance of mycotoxicoses for humans and animals. In: German veterinary weekly. 1989, pp. 335-338.
2. ↑ Thalmann: Conditions for the formation of mycotoxins in feed. In: German veterinary weekly. 1989, Vol 96, pp 341-343.
3. ↑ [1] , Martin Felsner and Dr. Katja Schwertl-Banzhaf, Bavarian State Office for Health and Food Safety, November 16, 2010
4. ↑ Media release from the agricultural research institute Agroscope Reckenholz-Tänikon ART .
5. ↑ HU Melchert, E. Pabel: Reliable identification and quantification of trichothecenes and other mycotoxins by electron impact and chemical ionization-gas chromatography-mass spectrometry, using an ion-trap system in the multiple mass spectrometry mode - Candidate reference method for complex matrices. In: Journal of Chromatography. (2004), A 1056, pp. 195-199, PMID 15595550 .
6. ↑ Elise Teichmann, Frank Mallwitz: Industrial quality control of oats, wheat and other types of grain with DON and T-2 / HT-2 analysis. In: Mühle + mixed feed. 150th year (2013), issue 11, pp. 332–336 ISSN  0027-2949 .
7. ↑ Regulation (EC) No. 1881/2006 setting the maximum levels for certain contaminants in food.
8. ↑ Ordinance of the EDI on the maximum levels for contaminants In: admin.ch , accessed on February 12, 2020