Herbal tea: transfer of mycotoxins from matrix into infusion

Herbal supplements are natural products, which are traditionally considered "helpful or at least harmless" for health promotion. Consumption of herbal products increases, but their safety, especially mycotoxin contamination, is still poorly controlled. Recent surveys report the occurrence of Aspergillus and Penicillium metabolites (aflatoxins (AFLs), ochratoxin A (OTA), cyclopiazonic and mycophenolic acids (MPA), sterigmatocystin (STE), citrinin), Fusarium (trichothecenes, zearalenone (ZEA), fumonisins (FBs), enniatins (ENNs)) and Alternaria (alternariol (AOH), its methyl ether (AME), tentoxin (TTX) and tenuazonic acid) toxins. A significant part of herbal supplements is consumed in the form of infusion. Thus correct risk assessment needs evaluation of mycotoxins transfer rates from the herbal matrix into the solution. We have studied the transfer of AFLs, OTA, STE, deoxynivalenol (DON), ZEA, FBs, T-2 and HT-2 toxins, AOH, AME, TE, ENNs, beauvericin and MPA from the spiked herbal matrix into infusion at different pH and total dissolved solids (TDS) characteristics of the water used for its preparation. Analytes were detected by HPLC-MS/MS. Transfer rate proved to be dependent on mycotoxins polarity and pH of the resulting infusion. TDS did not affect transfer significantly. ENNs, BEA, STC, ZEA and AOH transfer into infusion was below 25%; AFLs – 25-45%; DON, TTX and T-2 toxins – 60-90%, FB1 – 80-100%. The concentration of OTA, MPA and FB2 in the infusion depended on its pH. At pH about 4, it proved to be about 20%, 40% and 60% correspondingly. The increase of infusion pH led to almost complete transfer of these mycotoxins into the solution. The study of naturally contaminated samples supported the results of the model experiments.