Mycotoxin

Mycotoxins ( mold toxins ) are secondary metabolites of molds that are toxic even in very small amounts in vertebrates. In contrast, the major toxic components of fungi referred to as mycotoxins. A disease caused by mycotoxins is called mycotoxicosis.

Meaning / occurrence

Since time immemorial, mold infested food and thus mycotoxins are consumed. Since 1960, the first time you went about it serious thought, as thousands of turkeys died in England moldy peanut meal. The intensive search for the toxic substances then led to the discovery of the aflatoxins. In the USSR occurred during the Second World War to a disease, which had an inhibition of the formation of white blood cells to the cause and was based on moldy moldy millet and wheat. Only years later was the causative disease mycotoxin T2 toxin from the group of trichothecenes produced by Fusarium species, discovered that occurred in Russian grain samples with a concentration of up to 2.5%.

There are now about 200 different toxins known to be produced by over 300 species of fungi, the production of a particular toxin may be limited to a few specific types, but can also be accomplished by many species of several genera. The optimum conditions for the formation of the toxin and the growth of the mold need not necessarily coincide. Most mycotoxins are highly resistant to heat and acid treatment.

The formation of mycotoxins undergoes significant regional and seasonal variation and is dependent on the food supply, water content in the substrate and the surrounding air ( humidity), temperature, pH and interactions with other fungi. For the poison formation substrates are preferred, which are rich in carbohydrates complex composition.

Man is primarily threatened by contamination in food. All moldy foods may contain mycotoxins.

• Primary contamination: grain was infested already on the field of molds (eg ergot on rye, wheat, barley)
• Secondary contamination: in-stock moldy foods (such as Aspergillus or Penicillium spp.)
• Carry over: farm animals take on moldy food and give the poisons contained in the products continue to milk, egg, meat

The FAO estimates that about 25 % of world food production contain mycotoxins. Most often burdened with Fusarium toxins are cereals (especially maize and wheat). Affected by aflatoxin contamination are often agricultural products from tropical and subtropical areas, since the fungus Aspergillus flavus only grows well at temperatures of 25-40 ° C. Affected thereby are mainly maize and especially oil -bearing seeds and nuts, such as pistachios, peanuts, almonds and Brazil nuts. Mycotoxins can in humans and in animals at low concentrations exhibit toxic effects. Symptoms of poisoning include liver and kidney damage, impairment of the immune system, skin and mucous membrane damage or hormonal effects, such as reproductive disorders. Some mycotoxins are carcinogenic and can cause genetic damage.

Effect

Mycotoxins can develop diverse, mostly very adverse effects in humans and animals. In particular, they can

• Cause cancer ( carcinogenic )
• The central nervous system damage ( neurotoxic effect )
• Damage the immune system ( immunosuppressive effect )
• The genetic damage ( mutagenic effect )
• The fetus damage ( teratogenic effect )
• Organ damage (eg, liver or kidney) cause ( act hepatotoxic or nephrotoxic )
• When touched cause skin damage ( skin irritation to necrosis)
• Inhibit or initiate enzymatic metabolic processes
• Cause allergic reactions

A number of mycotoxins have the ability to inhibit bacteria from multiplying. This is called an antibiotic effect and uses this property in various drugs against bacterial infections.

Species

Mycotoxins can be summarized according to them producing mold species to groups of substances either because of a similar molecular structure, or:

• Aflatoxins
• Alternaria toxins, such as Alternariol ( AOH ), Alternariolmonomethylether (AME ), and Altenuen Tenuazonsäure
• Fumonisins
• Fusarium toxins
• Ergot alkaloids ( ergot alkaloids )
• Ochratoxins
• Trichothecenes such as deoxynivalenol (DON), nivalenol, T -2 toxin

Strictly speaking, the ergot alkaloids to the fungal toxins be expected, as the producer, the ergot ( Claviceps purpurea), is one of the major fungi, as in spring small but clearly visible fruiting bodies grow from the sclerotia.

List of mycotoxins (selection)

Ethanol ( ethyl alcohol), the (especially Saccharomyces cerevisiae ) is produced in the anaerobic metabolism of sugars by some yeasts, one of the primary metabolites and is therefore not to be among the mycotoxins in the strict sense.

Detection methods

For mycotoxin analysis, there are several physico-chemical methods:

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

In these studies, the substances are extracted with organic solvents from the test material and purified in complex process as and concentrated that there is clear evidence without interfering substances is possible. The HPLC/MS- and GC / MS couplings allow both the secure identification and quantification of various mycotoxins. For gas chromatography usually derivatives are used (eg trimethylsilyl derivatives ). When using the HPLC / MS coupling also underivatized mycotoxins can be measured. Electron impact ionization as both the (EI ) and the chemical ionization (CI) with quadrupole and ion trap mass spectrometers are possible. For the fast detection in the raw material intake in food and feed industries (especially for DON and ZEA ), there are immunological ELISA method and mycotoxin test strips ( " dipstick "), which according to the method of " Kapillardiffusionstests " or "flow -through tests " working. Recently there is also homogeneous Rapid Kinetic assays which allow a precision rapid tests an accurate quantitative determinations in under 15 minutes.

Maximum Regulations

EU applies (EC) 1881/2006 Commission Regulation fixing the maximum levels for certain contaminants in foodstuffs as of 19 December 2006 Regulation.