Herbs and herbal infusions: Determination of natural contaminants (mycotoxins and trace elements) and evaluation of their exposure

Abstract

Herbal infusions are amongst the world's most popular and widely enjoyed beverages, due to both large variety and convenience. However, natural contaminants, such as mycotoxins and trace elements can accumulate in aromatic herbs, which may have serious food safety and public health implications. In this study, the presence of mycotoxins, as well as the content of trace elements was evaluated in herbs and herbal infusions commercialized in Brazil. For the determination of fourteen mycotoxins, including the emerging mycotoxins enniatins (EN), beauvericin (BEA), and sterigmatocystin (STE), a liquid-chromatography tandem mass spectrometry (LC-MS/MS) method was validated. Overall, 42 out of 58 herb samples (72%) were contaminated, being BEA the most usual mycotoxin, present in 43% of the samples, followed by STE and HT-2 toxin, present in 37% and 24% of the samples, respectively. In herbal infusions, the occurrence of mycotoxins was 88% lesser than those verified in raw products. Despite these low levels, the hazard quotient (HQ) calculated revealed a potential health concern for HT-2 in infusions. The margin of exposure values for aflatoxins (AF), and ochratoxin A (OTA) from six herbal infusions were below 10,000, indicating also potential health risks. The twenty-one trace elements comprising toxic elements such as arsenic (As), cadmium (Cd), and lead (Pb) were determined in herb raw materials by inductively coupled plasma-mass spectrometry (ICP-MS). The levels of trace elements in herbs were very varied, with aluminum (Al) presenting the highest amount. The levels of legislated elements (As, Cd, Pb) analyzed in herbs were lower than 3.03 µg g−1 (Pb), thus not exceeding the legal limits defined for herbal medicinal by both European and Brazilian pharmacopeia.