Detection of multi-mycotoxins in rooibos and other consumed teas in South Africa by a modified QuEChERS method and ultra-high performance liquid chromatography tandem mass spectrometry

Globally, tea is the second most consumed drink next to water as it is considered healthy with is medicinal properties. A total of 100 tea samples obtained from registered shops within South Africa were extracted using a validated QuEChERS extraction method followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) analysis. The suitability of the analytical method for all the analyzed mycotoxins was determined based on the recoveries (which ranged from 100 to 117%), linearity (>0.99), precision (6–29%) among other satisfactory performance characteristics. The results revealed that three of the aflatoxins i.e., AFB1, AFB2, AFG2, ochratoxin A (OTA) and zearalelone (ZEA) were not detected in all the samples analyzed, nonetheless AFG1 was detected at low concentrations (1.72–5.19 μg/kg), which were below the levels regulated in food by the EU Commission Regulation 1881/2006. The low contamination profile of mycotoxins in tea necessitates their continuous monitoring to ensure product safety. Nonetheless, since this is the first study of mycotoxin contamination of teas in South Africa, it is thus essential to conduct more studies on diverse kinds of tea for mycotoxins regulation in the country.