Mykotoxins
Mycotoxins are toxic metabolic products of molds. They enter human food either during the cultivation of food plants (primary contamination), their storage (secondary contamination) or – in the case of animal foodstuffs – via moldy feed (carry-over). In the literature, the number of mycotoxins identified to date is given as 300-500 individual substances. The toxicity of these substances differs strongly. Also, there are numerous different mycotoxin-producing mold species. Roughly speaking, the most important mycotoxins can be assigned to the mold genera Aspergillus, Penicillium, Fusarium, Alternaria and Claviceps. Aspergillus and Penicillium are particularly noteworthy, as the aflatoxins produced by this genus are among the strongest naturally occurring carcinogenic substances. The ergot alkaloids formed by Claviceps purpurea were the cause of the dreaded disease known in the Middle Ages as “St. Anthony's fire”.
Cereals, fruit, nuts and oilseeds are among the foods most frequently contaminated with mycotoxins. The FAO (Food and Agriculture Organization of the United Nations) estimate that around 25% of the world's harvests are contaminated with mycotoxins must be viewed with care, as serious differences can occur depending on the toxin and country.
There are hardly any reports of acute poisoning with mold toxins (mycotoxicoses). The long-term effects of chronic ingestion of mycotoxins are more serious. The connection between liver cancer and an increased intake of aflatoxins, neurological complaints and even the death of limbs caused by ergot alkaloids or an immunosuppressive effect of some Fusarium toxins is very well documented.
Our group specializes in the analysis of Fusarium and Alternaria toxins. Molds of the genus Fusarium mainly attack cereal plants in the field, leading to significantly reduced harvests, smaller grain sizes and poorer baking properties. The most common Fusarium-related plant diseases are Fusarium head blight in wheat and barley, and Fusarium ear rot in maize. Trichotecenes, fumonisins and zearalenone are among the most important Fusarium toxins. Molds of the Alternaria genus can attack plants directly and cause characteristic plant diseases, but also grow very well on stored agricultural products. Cereals, potatoes, fruit, vegetables and oilseeds are frequently affected by Alternaria infestation. In contrast to many Fusarium toxins, there are currently no legal maximum levels for Alternaria toxins in the EU, only guideline values for the most important substances (alternariol, alternariol monomethyl ester and tenuazonic acid). Due to the structural diversity of Alternaria toxins, analysis is sometimes difficult.
Apart from well-researched mycotoxins, which are regulated by legal maximum levels, there are a number of substances whose toxicological significance for human health must be classified as critical and which are therefore currently the focus of research. These are referred to as “emerging mycotoxins”, for which there are still few toxicological values and data on their occurrence in food. At the Chair of Analytical Food Chemistry, we develop multi-methods with a special focus on “emerging mycotoxins”. In particular, we use the technique of stable isotope dilution analysis and produce the required isotope-labeled internal standard ourselves, either by chemical synthesis or by isolation from cultures.
Exemplary projects include
- the analysis of Fusarium toxins in barley malt, in particular the behavior during the brewing process
- the drone-based evaluation of Fusarium infestation in barley fields,
- the quantification of Alternatia and Fusarium toxins in plant-based milk and meat substitutes.
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