Do tea plantations use pesticides? How to detect their residues?

Do Tea Plantations Use Pesticides?

Yes, tea plantations may use pesticides during cultivation. The main reasons include:

Pest and Disease Control: Tea plants are susceptible to pests (e.g., tea green leafhopper), diseases (e.g., blister blight), and weeds. Pesticides can effectively control these threats, ensuring tea yield and quality.
Current Usage: Pesticide use is relatively common in modern tea plantations but is subject to strict regulations. Many plantations are transitioning to organic farming (e.g., obtaining organic certification) to reduce or avoid pesticide use, responding to consumer demand for food safety and environmental protection.
Food Safety Risks: Excessive pesticide residues can harm human health (e.g., carcinogenicity, neurotoxicity). Therefore, countries have established Maximum Residue Limits (MRLs). When pesticides are used rationally and regulations are followed, residue levels are typically safe and controllable.

How is Pesticide Residue Detected?

Pesticide residue detection primarily uses laboratory analysis and rapid testing methods to ensure tea complies with food safety standards. Common methods include:

Laboratory Testing Methods (High precision, suitable for batch samples)

Chromatography:
- Gas Chromatography (GC): Used to detect volatile pesticides, such as organophosphates.
- High-Performance Liquid Chromatography (HPLC): Suitable for thermally unstable pesticides, such as carbamates.
Mass Spectrometry:
- Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Mass Spectrometry (LC-MS): Provide high sensitivity and accuracy, capable of detecting multiple residues simultaneously.
Enzyme-Linked Immunosorbent Assay (ELISA): Based on antibody-antigen reactions, used for rapid screening of specific pesticides (e.g., pyrethroids), with lower costs.

Rapid Testing Methods (Field applicable, suitable for preliminary screening)

Test Strips or Kits: Such as immunochromatographic strips. Simple to operate (add sample and observe color change), results within minutes, commonly used for spot checks in plantations or markets.
Biosensor Technology: Utilizes enzymes or microorganisms for rapid response to pesticide residues; portable devices enable real-time monitoring.

Testing Process and Standards

Sampling: Random collection of samples from plantations or finished tea products.
Sample Preparation: Samples undergo extraction and purification (e.g., solid-phase extraction) to remove impurities.
Analysis: Application of the above methods to determine residue levels, comparing them against MRL values in international standards (e.g., China's GB 2763, EU's EC 396/2005).
Result Application: Non-compliant samples must be destroyed or treated to ensure tea is safe for market. Consumers can verify safety by checking product test reports (e.g., SGS certification).