REPORT OF THE WORKING GROUP ON TEA BREW BY T C CHAUDHURI N MURALEEDHARAN ANOOP KUMAR BAROOAH ON BEHALF OF RESIDUE SCIENTISTS WORKING AT TRA, JORHAT & UPASI TRF, INDIA
Decisions in the 18 th Session IGG, Hangzhou, 14-16 May 08. REPORT OF THE WORKING GROUP ON TEA BREW Combine existing methodology of measuring residues in tea brew, risk assessment and solubility of chemicals for establishing MRL Collect data on tea brew as well as leaf for same sample Investigate legal considerations for establishing MRLs by this method Consult with related international agencies, e.g. JMPR, Codex and national authorities.
Action Taken Report REPORT OF THE WORKING GROUP ON TEA BREW Working Group deliberated at Rome on 20-22 May 09 to draw action plan and decided to: Establishment of methodology for residue estimation in both dry tea and brew Organizing ring tests for residue estimation in BT, GT samples drawn from experiments sprayed with Bifenthrin, Imidacloprid, Dimethoate in 10 labs in different countries. Policy Actions- Document preparation by China, India Methodology & Expt.- China (GT), India (BT) Funding So far own cost
REPORT OF THE WORKING GROUP ON TEA BREW *After the Rome meeting, details were worked out to implement the decisions taken identifying tasks, areas of work, individuals, time bar for each action and circulated to all countries. *TRA prepared field trial samples for BT and China for GT, and sent to all labs for estimation, reporting. *Samples analyzed and reports received from 6 labs, lately 1, compiled and analyzed. *Report on GT with comments presented by Prof Chen. *Analysis on BT data are now presented below:
REPORT OF THE WORKING GROUP ON TEA BREW Summary of Results Labs reported 6 Parameters Residues (mg/kg) Mean SD RSD (Relative SD %) PRSD (Predicted Relative SD) Z score HorRat value Chemical Residues Bifenthrin BT & Brew Bifenthrin GT & Brew Imidachloprid BT & Brew Imidachloprid GT & Brew Dimethoate BT & Brew Dimethoate GT & Brew
REPORT OF THE WORKING GROUP ON TEA BREW Validation of method of analysis of pesticide residues in tea and brew. Method: SOP for Black Tea Table 1 Results for Bifenthrin residues in Black Tea Sl No Laboratories Residues (mg/kg) Mean (mg/kg)* SD (±)* RSD % PRS D Z score HorRat value 1 China Lab 1 1.910 0.45 2 China Lab 2 1.013 24.996 14.6-1.64 1.71 5 3 Ind. Lab 1 2.148 0.429 1.00 4 Ind. Lab 2 1.842 7 0.29 5 Sri Lanka Lab 1 1.670-0.11 6 Bangladesh Lab 1 0.043# 7 Kenya Lab 1 RNR 8 Indonesia Lab 1 RNR *Calculated for data from laboratories under SL No 1 to 5 only. # Data considered as outliers,rnr: Result not reported. SD: Standard Deviation; RSD: Relative Standard Deviation,PRSD: Predicted Relative Standard Deviation. 1.71
Sl No Table 2 Results for Bifenthrin residues in Black Tea Brew (liquor) Laboratories Residues (mg/kg) Mean (mg/kg)* SD (±)* RSD % PRS D Z score HorR at value 1 China Lab 1 0.022 47.26 26.75-0.61 1.77 2 China Lab 2 0.020-0.75 3 India Lab 1 <0.1 0.03-0.01 4 India Lab 2 0.052 1.43 1 5 5 Sri Lanka Lab 1 1.352# - 6 Bangladesh Lab 1 0.03-0.07 7 Kenya Lab 1 RNR 8 Indonesia Lab 1 RNR *Calculated for data from laboratories under SL No 1, 2, 4 and 6 only. # Data considered as outliers.rnr: Result not reported. SD: Standard Deviation; RSD: Relative Standard Deviation PRSD: Predicted Relative Standard Deviation
REPORT OF THE WORKING GROUP ON TEA BREW INFERENCES The performance of methods are satisfactory for Bifenthrin, Imidachloprid & Dimethoate as indicated from satisfactory Z score values from both BT & GT. The HorRat values were also within acceptable range for the methods except in case of Imidachloprid in BT & Bifenthrin from tea brew. Hence, the validation process may be repeated with more number of laboratories & with samples 3 day old from field trial to avoid working with the residues below detection limits (BOD).
REPORT OF THE WORKING GROUP ON TEA BREW 1. Methodologies for estimation of residue is amended and established for BT, GT, Brew as suggested by Prof Chen 2. For the same compound, single method for estimation of residue for dry tea and brew is required 3. For validation of methods, analysis of data following international protocol is to be made 4. There is enough evidence that tea brew contains only a fraction of residue present in dry tea, which depends on the polarity of compounds. 5. Legal consideration is to be framed SUMMARY
REPORT OF THE WORKING GROUP ON TEA BREW CONCLUSION 1. Repetition of experiments for validation of methods is essential in the next phase. 2. Discussions with JMPR experts for framing legal document is required now. 3. Preparation of document with legal support for submission to Codex is essential in the next phase. 4. Constant monitoring of progress is a must if MRL in tea Brew is to be a successful venture.
THANK YOU acknowledging help and support and inspiration received from all concerned in the scenario, particularly from B. Banerjee, C S Bedi and R Sen.