Studying the contamination of tea and herbal infu-sions with myсotoxins (Message 2)

Abstract

The occurrence of wide spectrum of mycotoxins has been studied in C. sinensis and herbal tea available in the Russian Federation by ultra high performance liquid chromatography coupled to tandem mass spectrometer (UHPLC-MS/MS). The batch of 77 samples consisted of 54 samples of bulk loose (prepacked) and packed C. sinensis tea and 23 individual and mixed herbal teas. The list of determined analytes included 29 mycotoxins: regulated in food (aflatoxins, ochratoxin A, deoxinivalenol, fumonisins, T-2 toxin and zaeralenone), their derivatives and structural analogues (A- and B-trichothecenes, mycotoxins of zearalenone group) and emerging mycotoxins (sterigmatocystin, mycophenolic acid, enniatins, beauvericin, Alternaria toxins). Samples of green and black C. sinensis tea were almost negative or contaminated at about LOD levels. Herbal teas, especially multi component, proved to be the most contaminated. Co-occurrence of several analytes (over five), including regulated and emerging mycotoxins, has been detected. The most frequent pattern was mycopenolic acid, Alternaria mycotoxins (tentoxin, alternariol and its methyl ether), enniatin B, beauvericin and sterigmatocystin. Beauvericin, enniatin B and mycophenolic acid were common for all types of studied tea samples. The study of the toxinogenic properties of tea mycoflora in vitro showed the ability of toxigenic species of molds to produce significant quantities of several types of mycotoxins, including emergent, simultaneously. The production of mycotoxins by molds on a substrate of C. sinensis green tea leaves has been 290 and 5600 μg/kg of fumonisins B1 and B2 correspondingly, 130 μg/kg of zearalenone, 14 μg/kg of sterigmatocystin and 160 μg/kg of alternariol methyl ether. These results indicate a potential risk of herbal teas to human health associated with wide spectrum of mycotoxins, especially emerging ones. Their regular monitoring in tea and data accumulation is necessary to assess the safety of this type of food products. The present study is the first attempt to estimate contamination of tea available in Russia with toxigenic mold and their secondary metabolites.

Keywords

• mycotoxins; emergent mycotoxins; fungal contamination; in vitro mycotoxin production; c. sinensis tea; herbal tea; uhplc-ms/ms