Mycotoxins is the collective term for various toxins produced by different types of mould. These are metabolic products of moulds that are produced by them for defence purposes, among other things. Mycotoxins are highly toxic to humans and animals and can lead to illness even in very small quantities. These poisonings are known as mycotoxicoses.

To date, over 250 species of mould have been discovered, which produce a total of over 300 different mycotoxins. However, there are only a few of these that can lead to actual contamination (pollution) of feed and food. These mycotoxins, which are important for humans and livestock, are divided into the following classes:

• Aflatoxins
• Alternaria toxins
• Fusarium toxins: Deoxynivalenol, T2 and HT2 toxin, fumonisins, zearalenone
• Ergot alkaloids (ergot alkaloids)
• ochratoxins
• patulin
• citrinin

Depending on the mycotoxin group, there are different foods that can be identified as a potential source of danger. Experience has shown that mycotoxins are generally found in cereals and cereal products including maize, in nuts, especially pistachios, as well as in fruit and dried fruit.

Fusarium toxins and ergot alkaloids 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 mainly ingested through oatmeal.

The typical sources of fumonisins and zearalenone are maize and maize products.

While aflatoxins are mainly ingested via hazelnuts and pistachios, it is also possible to ingest aflatoxins that enter livestock via feed, milk or eggs.

Patulin is mainly ingested with apple juice and ochratoxin A with bread and pastries.

Citrinin is mainly ingested 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 single consumption of a substance. Acute effects generally relate to a maximum period of 24 hours. Acute effects include gastrointestinal disorders such as vomiting, diarrhoea and loss of appetite, but also damage to various organs such as the liver, kidneys, skin or nervous system, as well as impairment of the immune and endocrine systems.

Chronic effects of a substance only become noticeable after a longer period of time and are associated with the regular consumption of a certain substance. This is at least one year, but often many years. Chronic effects include damage to various organs and a carcinogenic effect, as well as an effect that causes malformations in the embryo.

Within the EU, the maximum levels for certain mycotoxins in various food groups set out in the Contaminants Regulation 2023/915 are binding for producers and retailers. The following mycotoxins are regulated here: Aflatoxins, ochratoxin A, patulin, citrinin, ergot scerlotia and ergot alkaloids and fusarium toxins (deoxynivalenol, zearalenone, fumonisins, T2 and HT2 toxin). The foodstuffs in question are regularly checked for compliance with the maximum levels as part of official controls.

The group of Alternaria toxins comprises over 70 different toxins, of which only a few have been chemically and toxicologically characterised to date. Only a limited number of findings on the toxicity of the various Alternaria toxins are available from in-vitro and animal studies. Accordingly, it is not possible to make a statement about health effects on humans.

Fusarium toxins include many different mycotoxins produced by moulds 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 mainly lead to acute health effects such as loss of appetite, nausea and vomiting. However, these effects are only to be expected at extremely high concentrations, which are unusual in human nutrition. Their chronic effects include growth retardation and a weakening of the immune system, which is associated with an increased susceptibility to infection
• The negative health effects of zearalenone include, in particular, oestrogenic effects. Female pigs are considered to be the most sensitive group. The adverse effects include various effects in the reproductive area, such as impaired formation of sex hormones, changes in the reproductive 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 that can cause general impairments as well as disorders of the blood and immune system

Ergot alkaloids(especially ergotamine) posed a major 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 ergotism. The ingestion of ergot alkaloids leads to a severe constriction of the blood vessels, resulting in a variety of symptoms such as headaches, general confusion, vomiting and even sensory disturbances and skin tingling due to the undersupply of 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 labour-inducing effects of these alkaloids, for which it was sometimes used in the Middle Ages.

Acute ingestion ofpatulin can lead to gastrointestinal disorders, nausea and ulceration. Findings from animal studies indicate a mutagenic effect after chronic ingestion. Findings on a possible carcinogenic effect have so far been contradictory.

Aflatoxins are toxic to the liver on the one hand and carcinogenic and mutagenic on the other. Studies on population groups have clearly shown that aflatoxins are involved in the development of liver cancer. Aflatoxin B1 is generally recognised as the most toxic toxin in this group. The metabolic products of aflatoxins released by farm animals via milk or eggs are also dangerous for humans, which is why aflatoxin levels are strictly controlled throughout the EU, not only in food but also in animal feed.

Ochratoxin A accumulates in the kidneys in particular and can damage them in the long term. Animal studies have also shown that chronic exposure to ochratoxin A can lead to kidney tumours.

Citrinin also has a damaging effect on the kidneys.