Occurrence of Aspergillus chevalieri and A. niger on Herbal Tea and Their Potential to Produce Ochratoxin A (OTA)

Herbal teas, including Camellia sinensis (black and green teas), are popular beverages with health benefits for consumers worldwide. These products are prepared from natural materials of different plant parts containing antioxidant properties and vitamins. The aim of this study was to investigate fungal contaminants and their ability to produce ochratoxin A (OTA) in herbal tea samples. Seven herbal teas were obtained from local markets in Chiang Rai, northern Thailand. Samples were incubated on potato dextrose agar (PDA), and the growing mycelia were isolated into a pure culture. The cultures were identified via both morphology and molecular analysis to confirm species identification. The identified species were subjected to OTA analysis using high-performance liquid chromatography (HPLC) with a fluorescence detector. Ochratoxin A was produced by Aspergillus chevalieri and A. niger, isolated from seven herbal tea samples (black tea, green tea, bael fruit, goji berry, jasmine, lavender, and rose). This finding raises concerns about the safety of herbal tea and should be investigated further for potential health implications.