Researchers call for the development of regulations to ensure the safety of herbal teas

In January 2018 researchers from Italy published the results of their analysis of 32 samples of commercially available black and green teas which had been purchased from markets and online-shops in southern Italy. It is known that the improper storage of herbal tea (long periods, humid environments) is a potential health hazard due to the growth of bacteria and moulds, and in this study the researchers evaluated the different pathogens found in the samples together with the amount of viable bacterial or fungal cells.  Results showed that for over 80% of samples the microbial load was between 1.0 × 102 and 2.8 × 105 CFU/g tea. Pathogens isolated included Pseudomonas psychrotolerans, Staphylococcus warneri, Pantoea gaviniae and one strain of Clostridium perfringens. Fungi were isolated from 70% samples, the most prevalent mould isolated being Aspergillus niger strains, followed by Aspergillus tubingensis.  Ochratoxin A was also detected in 22 of 32 tea samples, the concentration being above the recommended limit for food products in 50% of samples (according to European and American guidelines).

Carraturo F et al. Comparative assessment of the quality of commercial black and green tea using microbiology analyses. BMC Microbiol. 2018 Jan 5;18(1):4.

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