Analysis of Pesticides in Organic and Conventionally Farmed Green and Black Teas

Harms zum Spreckel H., Pfeif S., Kroschwald J, Büttner S., Czczatka V., Witt G., Ronczka S.
Analysis of Pesticides in Organic and Conventionally Farmed Green and Black Teas
Poster im Rahmen des 16th European Pesticide Residue Workshop in Rotterdam (EPRW 2026), 09.06.-12.06.2026

Abstract:

In tea cultivation, pesticides such as herbicides, insecticides, and fungicides are utilized to secure and stabilize crop yields. To ensure consumer safety, the European Union enforces strict Maximum Residue Levels (MRLs) under Regulation (EC) No 396/2005, which apply to imported products as well. As part of the official control of food by the German federal states of Berlin and Brandenburg, in 2025 48 commercial tea samples, comprising 28 unfermented (Green and White) and 20 fermented (Black and Pu-erh) teas, including flavoured varieties such as Earl Grey and citrus flavoured green tea, were analysed for pesticide residues amenable with multi-residue methods. Utilizing the DFG S19 method for GC-MS/MS and the QuEChERS method for LCMS/MS, the samples were analysed for approximately 330 pesticide active ingredients. While the majority of samples were compliant, three teas (7.3%) exceeded MRLs taking in account the expanded measurement uncertainty. Furthermore, results revealed that 41.7% of all teas (20 samples) contained quantifiable residues, with 26.8% (11 samples) exhibiting multiple residues. Residues which were quantified at least four times or more were Chlorfenapyr (seven times), Clothianidin and Thiamethoam (six times), Bifenthrin (five times) and Acetamiprid and Cypermethrin (four times). This prevalence of multiresidue
findings highlights the significance of the "cocktail effect," where the synergistic toxicological impact of combined substances can only be fully
assessed through individual risk evaluations.

A significant disparity was observed between conventionally and organically grown teas: 62.5% of conventional teas contained residues, compared to 20.8% of organic samples. Notably, in all organic black teas no residues were quantified, while five organic green teas exhibited low amounts of pesticide residues. Since synthetic pesticides are prohibited in organic farming, these findings may likely stem from environmental drift or cross-contamination within the global supply chain rather than active application. For consumers seeking to minimize pesticide exposure beyond statutory limits, organic tea remains the recommended choice.