Evaluation of 9,10-anthraquinone contamination in tea products from Indonesian manufacturers and its carcinogenic risk to consumer health

This study aimed to determine 9,10-anthraquinone (AQ) levels in Indonesian tea products from different manufacturers and assess the AQ's associated health risks. AQ levels increased significantly during withering and drying stages, using pinewood as a heat source. Generally, black tea was highly contaminated by AQ followed by green tea, oolong tea, and white tea. Out of a total of 116 samples from manufacturers using wood pellets as a heat source, 13% (15/116) of samples were contaminated with AQ exceeding the EU maximum residue level (MRL), and after accounting for measurement uncertainty, this value decreased to only 2% (2/116) that were deemed non-compliant. In contrast, 88% (57/65) and 50% (7/14) of tea samples were contaminated with AQ exceeding the EU MRL when manufacturers used pinewood and palm kernel shells as heat sources, respectively. However, based on our estimation, the risk level due to AQ exposure from Indonesian tea is still manageable, as indicated by calculating incremental lifetime cancer risk, < 10⁻⁶ across all conditions studied (age group, type of tea, and heat source).