Studying the contamination of tea and herbal infusions with mold fungi as potential mykotoxin producers: The first step to risk assessment (message 1)

Abstract

We analyzed microbe contamination of 54 tea samples (Camellia sp.), black and green one, including those with various additives, and tea infusions, including herbal ones. Tea that was not packed (semi-finished product) came from the following regions: India, Indonesia, Sri-Lanka, Vietnam, Kenya, China; packed tea was bought in retail outlets in the RF. Overall, 83.3 % samples of unpacked tea conformed to microbiological standards as per mold fungi; 16.7 % samples that didn't conform to them contained mold fungi in quantities equal to 1.3-8.2·103 CFU/g. We detected discrepancies in quantities of mold fungi in samples with different fraction structure of tea (in average CFU/g): large-leaved tea contained 2,3·102 CFU/g; middle- leaved, 7,4x102; small-leaved (including tea dust), 1,7·103. All packed tea samples (Camellia sp.), including those with additives, conformed to the requirements fixed by the existing standards. Aspergillus niger mold fungi prevailed in examined tea (Camellia sp.). We revealed substantial microbe contamination in herbal teas; 55 % samples didn't conform to the existing standards and contained more than 104-6 CFU/g of mold fungi. Besides, 72.2 % of these samples contained more than 105-8 CFU/g of bacteria; 62.5 % samples of herbal teas that conformed to the standards were contaminated with great quantities of bacteria equal to 8·105 - 2·108 CFU/g. We detected Aspergillus, Penicillium, Alternaria, Fusarium in herbal teas microflora; they were producers of hazardous mycotoxins, including emergent ones, and it could potentially cause contamination of herbal teas with mycotoxins. These data will be applied in future to identify hazards caused by mycotoxic fungi in tea and tea infusions as well as to update existing standards.