Currently, international pesticide residue testing for tea primarily targets dried tea leaves (unbrewed leaves). In Taiwan, where tea culture thrives, dried tea is also directly used in various products such as pastries, tea powder, and meals—not solely for drinking. Therefore, testing is conducted on the dried tea leaves themselves.

At the 2016 Codex Committee on Pesticide Residues (CCPR) meeting, the Indian representative proposed using a “brew factor” in the risk assessment process to help determine pesticide residue limits for tea. Following this, Taiwan’s Tea Research and Extension Station (TRES) began studying pesticide leaching rates to evaluate the feasibility of setting separate residue standards for brewed tea.

In Taiwan, all approved pesticides used in tea cultivation are fat-soluble. During brewing, the tea is diluted in water, meaning the amount of pesticide residue found in the brewed tea is significantly lower than that of the unbrewed leaves. You can safely enjoy tea that has passed certified pesticide testing.

Source: Tea Research and Extension Station, Taiwan Ministry of Agriculture
https://www.moa.gov.tw/faq_view.php?id=36