Mikotoxinok: előfordulás, toxikus hatások, védekezési stratégiák

Absztrakt

Mycotoxins are toxic secondary metabolites of molds, typically produced by Aspergillus, Penicillium, Fusarium, and Alternaria fungi. They appear as contaminants in animal feed and several foodstuffs (e.g., cereals, fruits, vegetables, oilseeds, spices, baked goods, dairy and meat products, eggs, dried fruits, fruit juices, milk, wine, beer, and coffee). The chemical structures and toxic actions of mycotoxins show large variations, including hepatotoxicity, nephrotoxicity, gastrointestinal toxicity, immunotoxicity, as well as carcinogenic and endocrine disruptor effects.

The most important regulated mycotoxins are aflatoxin B1 and M1, deoxynivalenol, fumonisin B1 and B2, zearalenone, T-2 and HT-2 toxins, ochratoxin A, and patulin. In addition to the parent mycotoxins, their masked/modified metabolites can also contaminate crops and/or the corresponding food products, making the analytical detection/quantification of mycotoxins challenging. Moreover, several other so-called “emerging” mycotoxins can also be mentioned, where the limited data regarding their occurrence, exposure, and toxic actions make their proper evaluation difficult.

To prevent the appearance and spread of molds as well as to decrease mycotoxin contamination, it is important to use relatively resistant host plants, improved agronomic methods and pesticide management. Thereafter, the proper conditions for harvesting, drying, storing, cleaning, and sorting are also highly relevant. To decrease mycotoxin levels, some of the physical (e.g., washing, liquid extraction, heat treatment, radiation, and adsorbents), chemical (e.g., alkaline treatment and ozonation), and biological (e.g., microorganisms or their cell wall fractions, isolated enzymes) methods can be considered. Furthermore, certain food technology processes can also affect the final mycotoxin content in the end products.

Several strategies are being investigated to develop novel and effective mycotoxin binders. Cyclodextrins (CDs) and CD-based polymers seem to be promising candidates for this purpose. CD polymers have been successfully used to extract mycotoxins (e.g., alternariol, ochratoxin A, and zearalenone) from aqueous matrices, including beverages. These observations underline that CD technology can be a tool for the analytical extraction/enrichment of mycotoxins and/or decrease toxin levels in contaminated drinks. In addition, CDs showed significant protective effects against alternariol- and zearalenone-induced toxicity in cell experiments and zebrafish embryo models. Therefore, CDs may provide a new strategy to relieve the toxic impacts of mycotoxins.