Fusarium toxins

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Fusarium toxins are mycotoxins , which are mainly formed as secondary metabolic products by Fusarium , a species of mold that is widespread worldwide . Fusarium toxins can cause severe poisoning ( toxicosis ) in humans and animals via infected food and feed .

There are different groups of Fusarium toxins according to their chemical structure:

Trichothecenes

This group includes over 50 toxins, which are divided into four categories. A- and B-trichothecenes appear most frequently. The molecular backbone is a tetracyclic 12-epoxytrichothec-9-ene ring system, with B-trichothecenes differing from type A by a carbonyl group in C-8. They are considered to be acutely toxic. The IARC classifies trichothecenes in category 3 and thus as not causing cancer. In addition to the local grain varieties oats and wheat, maize in particular is affected by trichothecene-forming fusarium strains. A carry-over from feed grain to animal foods is excluded.

A-trichothecenes

Type A can be formed, for example, by infestation of useful plants with Fusarium sporotrichioides. In addition, A-trichothecenes are known to cause alimentary toxic aleukia (ATA). This occurred as early as 1900 in connection with infected, overwintered grain. In addition to grain, type A can also be found in potatoes and bananas.

B-trichothecenes

The most important mycotoxins in grain cultivation, however, belong to the trichothecenes type B. Particularly relevant representatives are deoxynivalenol (DON), nivalenol and diacetoxyscirpenol . They can be formed by F. graminearum, F. culmorum and F. crookwellense. These representatives of mycotoxins inhibit protein biosynthesis in particular and are therefore cytotoxic . In humans, poisoning can lead to vomiting, gastroenteritis , allergic skin reactions and impairment of the immune system. In farm animals, DON-contaminated feed causes growth retardation and increased susceptibility to infection by weakening the immune system.

Due to the frequent occurrence of B-trichothecenes in food, statutory maximum levels have been set for the trichothecene representatives DON, T-2 and HT-2 toxin. The maximum values ​​are 750 µg / kg in dry pasta, 500 µg / kg in bread and baked goods and 200 µg / kg in baby food. The Scientific Committee on Food of the European Union set a TDI of 1 µg / kg body weight for DON and a TDI of 0.7 µg / kg body weight for Nivalenon. The trichothecenes T-1 and T-2 are acutely toxic and have a total TDI of 0.06 µg / kg body weight. The cooking process can reduce exposure to trichothecene by transferring these water-soluble substances into the cooking water.

Zearalenone

Zearalenone and its derivatives (zearanol, zearalenol, zearalanol, zearalanone) belong to the group of lactones. They occur mainly in maize and are formed, for example, by F. graminearum and F. culmorum. However, this group of toxins is also known to occur in barley, oats, wheat, rice, millet and soy. Carry-over of mycotoxins can occur, which enter the human organism through the consumption of animal innards. Acute toxicity occurs only with very high intake, which is not achieved in practice. The estrogenic effect of zearalenone is caused by its binding to the estrogen receptor. In the case of high zearalenone intake, the following symptoms are observed in pigs as farm animals: changes in secondary sexual characteristics, disturbed menstrual cycles, pseudo-pregnancy, abortions , sterility. Humans also react to this mycotoxin group by causing disturbances in hormonal development. In addition, zearalenone is considered to be haematotoxic. Overall, zearalenone is not acutely toxic, teratogenic or genotoxic. According to the IARC, it is classified in category 3 and is therefore not considered to be carcinogenic.

The Scientific Committee on Food of the European Union has set a TDI of 0.2 µg / kg body weight. According to Regulation (EC) No. 1881/2006 2.5. the legal maximum amount for zearalenone in cereal products is 50 µg / kg, in maize-based products 100 µg / kg and in baby food 20 µg / kg. In EU-wide studies, 32% of the grain samples were contaminated with zearalenone, and 79% of the samples in maize. Zearalenone is broken down in noteworthy quantities through industrial processing and normal household preparation.

Fumonisins

Fumonisins are produced in particular by F. verticilloides and F. proliferatum on maize. Six fumonisins are currently known, of which only fumonisins B1 and B2 are important in foods. They are inhibitors of sphingolipid synthesis and thus disrupt the structure of the cell membrane. Furthermore, hydrolyzed fumonisins are also known, which in toxicological tests showed a greater toxicity. Fumonisin intake is suspected of having liver cancer in rats, and they are also believed to be responsible for the fatal leukoencephalomalacia in horses and a disease in pigs. They are suspected to cause esophageal cancer in humans. According to the IARC, fumonisins are assigned to category 2B and are therefore considered to be potentially carcinogenic.

For fumonisin B1 and the sum of fumonisin B1, B2 and B3, the Scientific Committee on Food of the European Union has set a TDI of 2 µg / kg body weight. According to Regulation (EC) No. 1881/2006 2.6, the legal maximum amount for fumonisins in unprocessed maize is 2000 µg / kg, ready-to-eat foods based on maize are 400 µg / kg and processed cereal-based foods (maize) are 200 µg / kg. In an EU-wide study, 46% of all grain samples were contaminated with fumonisins, with maize it was even 66%. The toxin concentration in imported maize from warm climates is particularly high. Most food production processes and the usual household preparation of food have no (inactivating) influence on the fumonisin content. At present it has not yet been clarified whether further toxic compounds arise during production processes or whether these are bound to certain food components.

literature

  • L. Roth, H. Frank, K. Kormann: Poison mushrooms · Mushroom poisons. Molds Mycotoxins. Occurrence, ingredients, fungal allergies . ecomed, Landsberg am Lech 1990, ISBN 3-609-64730-2 .
  • M. Bretz: Production, analysis and degradation of selected Fusarium toxins [Münster] 2006, DNB 980261821 (dissertation University of Münster (Westphalia) 2006, 139 pages).
  • H. Knapp Trichothecene Bavarian State Office for Health and Food Safety, 2019

credentials

  1. ↑ Regulation (EG) No. 1881/2006 Annex section (consolidated version of March 19, 2018)
  2. ↑ Regulation (EG) No. 1881/2006 Appendix Section 2.5 (consolidated version of March 19, 2018)
  3. ↑ Rapp, Martin; Berger, Matthias Zearalenon , Bavarian State Office for Health and Food Safety, 2019
  4. ↑ Regulation (EG) No. 1881/2006 Appendix Section 2.7 (consolidated version of March 19, 2018)
  5. ↑ Rapp, Martin; Berger, Matthias Fumonisine , Bavarian State Office for Health and Food Safety, 2012
  6. ↑ Michael Bretzt (* 1978 Sintana , according to DNB), food chemist , see also his work on taurine .