Prevalence of mycotoxin contamination in different types of tea: a systematic review and meta-analysis

The consumption of tea as a beverage is considerably increasing worldwide. However, some questions are raised about its safety, particularly regarding the potential contamination by mycotoxins. The objectives of this systematic review and meta-analysis were to assess the overall prevalence of mycotoxin contamination in different types of tea (black, green, dark, white and pu-erh), to compare the contamination rate between two periods (2000-2017 and 2018-2022), and to investigate the impact of country's income on this contamination. Included studies were selected from Scopus, Science Direct, Web of Science, PubMed and Google Scholar research databases, according to PRISMA guidelines. Statistical analysis was performed using MecdCalc software. Concerning the analytical methods used for mycotoxin detection, 84.6% of included studies used HPLC and or LC-MS/MS. In the 21 included studies, the mycotoxin contamination was predominantly by deoxynivalenol, with 43.8% (95% CI: 8.2%- 83.8%), followed by ochratoxin A (29.1% (95% CI: 11.9%- 50.2%)), enniatin (23.7% (95% CI: 1.7%- 60.1%)), citrinin (23.6% (95% CI: 6.2%- 47.8%)), zearalenone (17.8% (95% CI: 5.1%- 36.0%)), and aflatoxins (12.4% (95% CI: 7.8%- 17.9%)). Regarding tea categories, black tea was the most contaminated type, with a rate of 89.2% (95% CI: 73.9%-98.3%), followed by green tea with a rate of 67.3% (95% CI: 37.0%-91.2%). The contamination prevalence was higher in studies conducted before 2018 than those of the 2018-2022 period, and lower in high-income countries compared to middle and low-income countries, where tea contamination was rarely reported. Therefore, more stringent prevention strategies, including regulatory measures, are needed to decrease the risk of tea consumers exposure to mycotoxins.