Mycotoxins is the collective term for various toxins produced by different mold species. These are metabolic products of molds, which are produced by them, among other things, for defense. Mycotoxins are highly toxic to humans and animals and can cause illness even in very small quantities. These poisonings are referred to as mycotoxicoses.
So far, more than 250 mold species have been discovered, which produce a total of more than 300 different mycotoxins. Among them, however, there are only a few that can lead to actual contamination (pollution) of feed and food. These mycotoxins, which are significant for humans and livestock, are divided into the following classes:
- Alternaria toxins
- Fusarium toxins: Deoxynivalenol, T2 and HT2 toxins, fumonisins, zearalenone.
- Ergot alkaloids (ergot alkaloids)
Depending on the mycotoxin group, there are different foods that can be identified as a potential source of danger. In general, experience has shown that mycotoxins are found in cereals and cereal products including corn, in nuts, especially pistachios, and also in fruit or dried fruit.
Fusarium toxins are mainly found in cereals and cereal products.
Deoxynivalenol is mainly ingested via cereal products, such as bread and pastries.
T2 and HT2 toxins occur predominantly in oats and are therefore ingested primarily through oatmeal.
The typical intake source of fumonisins and zearalenone is corn and corn products.
While aflatoxins are predominantly ingested through hazelnuts and pistachios, it is equally possible to ingest aflatoxins that enter farm animals through feed, such as milk or eggs.
Patulin is ingested mainly with apple juice and ochratoxin A with bread and pastries.
Citrinin is mainly absorbed via cereals and cereal products.
A distinction must be made between acute and chronic health effects.
Acute effects are impairments that are directly or briefly associated with the one-time consumption of a substance. Acute effects usually refer to a period of 24 hours or less. Acute effects include gastrointestinal disturbances such as vomiting, diarrhea, and loss of appetite, but also damage to various organs such as the liver, kidney, skin, or nervous system, as well as impairment of the immune and endocrine systems.
Chronic effects of a substance become noticeable only after longer periods of time and are associated with regular consumption of a certain substance. This is at least a year, but often many years. Chronic effects include damage to various organs, as well as a carcinogenic effect, and an effect that causes malformations in the embryo.
Situation in Austria
Within the EU, the maximum levels for certain mycotoxins in various food groups, issued via the Contaminants Regulation 1881/2006, apply and must be complied with by producers and traders. The following mycotoxins are regulated here: Aflatoxins, ochratoxin A, patulin, citrinin, ergot alkaloids and Fusarium toxins (deoxynivalenol, zearalenone, fumonisins, T2 and HT2 toxin). The foodstuffs concerned are regularly checked for compliance with the maximum levels as part of official controls.
Mold can enter a food product through damaged packaging or if stored incorrectly/for too long.
Food that shows mold should not be consumed. On the one hand, the mold might not have spread visibly in the food, on the other hand, the mycotoxins formed by the mold might spread in the food. This is especially true for foods with high water content, but also bread and other cereal products. Exceptions apply to foods with a very low water content, such as hard cheese or salami. In such foods, the mold can be removed by cutting it out generously.
In contrast, molds deliberately used during food production, so-called noble molds, are known not to produce mycotoxins and foods produced in this way are safe for human consumption.
The group of Alternaria tox ins comprises over 70 different toxins, of which only a few have been chemically and toxicologically characterized to date. Findings on the toxicity of the various Alternaria toxins are so far only available in limited numbers from in vitro and animal studies. Accordingly, a statement on health effects for humans is not possible.
Fusarium tox ins include many different mycotoxins produced by molds of the genus Fusarium. The best known representatives of this group include deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZON), but also lesser known mycotoxins such as fumonisins or T2 and HT2 toxins.
- Deoxynivalenol and nivalenol lead mainly to acute health effects such as loss of appetite, nausea and vomiting. However, these effects are only expected at extremely high concentrations, which are uncommon in human diets. Its chronic effects include growth retardation and weakening of the immune system, which is associated with increased susceptibility to infection
- Negative health effects of zearalenone include estrogenic effects in particular. Here, female pigs are considered the most sensitive group. The adverse effects include various effects in the reproductive area, such as disturbed formation of sex hormones, alteration of the sex organs, disturbances in the menstrual cycle, infertility, negative effects on the embryo
- Fumonisins are suspected to be carcinogenic in humans and to cause malformations in the embryo (spina bifida, open back)
- T2- and HT2-toxins are highly toxic substances, which can cause general impairments as well as disorders of the blood and the immune system.
Ergot alkaloids (especially ergotamine) posed a great threat to human health for a long time, as they contaminated entire grain harvests, especially rye. This led to masses of people falling ill with so-called ergotism. The ingestion of ergot alkaloids leads to a severe constriction of the blood vessels, resulting in many symptoms such as headaches, general confusion, vomiting, and even sensory disturbances and skin tingling due to the undersupply of the peripheral blood vessels. In extreme cases, this undersupply leads to the death of individual fingers or toes. The name ergot is due to the miscarriage and labor-inducing effects of these alkaloids, for which it was also partly used in the Middle Ages.
Patulin can cause gastrointestinal disorders, as well as nausea and ulceration when ingested acutely. Findings from animal studies indicate a mutagenic effect after chronic ingestion. Findings on a possible carcinogenic effect are contradictory so far.
Aflatoxins have a liver-toxic effect on the one hand and a carcinogenic and mutagenic effect on the other. Studies on population groups have clearly shown that aflatoxins are involved in the development of liver cancer. Aflatoxin B1 is generally considered to be the most toxic toxin from this group. Likewise, the metabolic products of aflatoxins released by farm animals via milk or eggs are dangerous to humans, which is why aflatoxin levels are strictly controlled not only in food but also in feed throughout the EU.
Ochratoxin A accumulates particularly in the kidneys and can damage them in the long term. Animal studies also show that ochratoxin A can lead to kidney tumors in the case of chronic exposure.
Citrinin also has a damaging effect on the kidneys.