WORKING GROUP ON MRLs IN BREW. Intersessional Meeting of the Intergovernmental Group on Tea Rome, 5-6 May 2014

Transcription

1 WORKING GROUP ON MRLs IN BREW Intersessional Meeting of the Intergovernmental Group on Tea Rome, 5-6 May 2014

2 INTERSESSIONAL MEETING OF THE FAO IGG ON TEA, ROME, ITALY, 5-6 MAY, 2014 REPORT OF THE WORKING GROUP ON MRL IN TEA BREW ( ) CHAIR: CHINA CO-CHAIR : INDIA & USA CO-ORDINATORS : PROF CHEN ZONGMAO DR A K BAROOAH MR PETER GOGGI

3 ACTIVITIES AND ACTION PLAN

4 Background In last intersessional Meeting held in Washington DC on Sep, 2012 Agenda points discussed Report on progress made with the CCPR regarding the use of the tea brew as an alternative to measuring MRLs. Consider the draft action plan outlined in the discussion document, define the framework of a policy document required for CODEX and agree on the strategy to include the tea brew in the dietary risk assessment for tea.

5 The group agreed on the following action plans 1. To prepare a detailed methodology and policy document on how to approach the regulators following acceptance at the 44th session of the CCPR of the proposal to fix MRLs in tea based on risk assessment using the brew factor 2. To organize a ring test on a few widely used pesticides among different tea producing and consuming countries (India, China, Sri Lanka, Kenya, UK, USA and Germany)

6 The objectives were.. Action plan Objective 1 Provide a guidance document for fixing MRLs in tea and would be circulated to all members to assist them to approach national regulators including manufacturers 2 Validate test methods for dry tea & brew to be carried out in different labs in India, China, Sri Lanka, Kenya, UK, USA and Germany

7 Status of work undertaken since the last meeting 1. Policy document entitled Guidance Document on Risk Assessment Using Brew Factor For Fixation of MRLs of Pesticides In Tea drafted jointly by India and China. 2. Ring Test for Black Tea organized. Field treated tea samples prepared at Tocklai, Tea Research Association, Assam, India containing incurred residues of acetamiprid, fenpyroximate, flubendiamide and propiconazole & test methods [based on Quechers LCMSMS] sent to 14 laboratories in China, India, Kenya, US and Germany. Results to be compiled by May 2014.

8 GUIDANCE DOCUMENT ON RISK ASSESSMENT USING BREW FACTOR FOR FIXATION OF MRLS OF PESTICIDES IN TEA [Prepared By Indian and Chinese delegations, Working Groups on MRL and Tea Brew of FAO-IGG on Tea with comments from USA, Japan and Sri Lanka]

9 The Concept. Main Reason for opposition to fixing MRL in tea brew Brew is not the commodity on sale Way to go forward Generation of data on residues in made tea and tea brew Determination of brew factor Risk assessment based on brew factor Data submission to regulators for MRL fixation in tea

10 This approach will ensure food safety as well as realistic MRLs in tea Will have more acceptability than setting MRLs in tea brew in general No contradiction with the purpose of Codex MRLs as MRLs for trade It will also not be unfair to growers with critical GAP Scope This document is applicable in assisting regulators, scientists or other competent bodies while fixing MRLs of pesticide in dry tea leaves (traded commodity) using brew factors for risk assessment. It is not applicable to Matcha tea.

11 Definitions and terms used in this document Black Tea: As defined in ISO 3720 (2011) Green Tea: As defined in ISO (2011) Dry tea leaves: Refers to any dry tea leaves of fermented tea (Black tea), semi-fermented tea (Oolong tea), non-fermented tea (Green tea, White tea) and post-fermented tea (Pu-er tea) Tea shoots: Fresh green tea shoots comprising mostly 2 leaves and a bud, plucked to produce dry tea leaves. Brew: Tea liquor produced by adding hot boiling water to dry tea leaves Brew Factor (BF) = Residues in tea brew Residues in dry tea leaves Processing factor (PF)= Residues in fresh tea shoots Residues in dry tea leaves

12 Procedure for determination of Brew Factor To determine the brew factor, the data on residues of a pesticide in both dry tea leaves and the residues in the tea brew prepared from the same dry tea leaves are required The residues in dry tea leaves are expressed in mg/kg. The residues in tea brew is the residues in tea liquor expressed in mg per kg of dry tea leaves used for preparing the brew. It is obtained by dividing the amount of residues in brew (mg) by the amount of dry tea leaves used (kg) for preparing the brew. Brew Factor = Residues in tea brew (mg/kg) Residues in dry tea leaves(mg/kg) Brew Factor has no units Percent transfer of dry tea residues into tea liquor = Brew Factor x 100

13 Residues of pesticides (mg/kg) in black tea and in tea brew and Brew Factor Pesticides Rate of application In field (kg ai/ha) RBT (mg/kg) RTB (mg/kg black tea used) Brew Factor (BF) (RTB RBT) Transfer into brew (BF 100) (%) Deltamethrin Bifenthrin Fenpropathrin Hexaconazole Propiconazole Note: 1. RBT: Residues in black tea. 2. RTB: Residues in tea brew. [Adapted from Barooah, et al, (2011)].

14 Residues of pesticides (mg/kg) in green tea and in tea brew and Brew Factor Pesticides Rate of application In field (kg ai/ha) RBT (mg/kg) RTB (mg/kg black tea used) Brew Factor (BF) (RTB RBT) Transfer into brew (BF 100) (%) Dimethoate Imidacloprid Acetamiprid Tolfenpyrad Indoxacarb Fenitrothion Malathion Chlorfenapyr Note: 1. RGT: Residues in green tea. 2. RTB: Residues in tea brew. [Adapted from Chen ZM et al, China].

15 Table 3 in the Document (page 4) Brew factors calculated from transfer rates reported for 38 pesticides in studies carried out in the period 1980 to 2013 From Chen Zongmao et al, (1980) to Hou et al (2013) as evident from 69 references quoted in the table... indicates Brew Factor increases with water solubility

16 Procedure for assessment of risk from pesticide residues in tea Risk assessment based on the residues in dry tea leaves In the current method, the Theoretical Maximum Daily Intake (TMDI) is computed from the Highest Residues (HR) or Supervised Trial Median Residues (STMR) from field trial data and the maximum daily consumption of tea (dry leaves). The TMDI so computed is then compared with the Acceptable daily Intake (ADI) per person This comparison of TMDI with ADI is actually a gross over estimation of potential risk to consumers as dry raw tea leaves are not usually consumed. As a consequence, such over estimation of risk will unduly eliminate a number of otherwise useful compounds. Use of Brew Factor will lower the TMDI to yield values at actual & will prevent undue overestimation of risk.

17 Procedure for assessment of risk from pesticide residues in tea Risk assessment based on the residues in dry tea leaves In the current procedure for establishing MRLs in tea, the Theoretical Maximum Daily Intake (TMDI) is computed from the Highest Residues (HR) or Supervised Trial Median Residues (STMR) from field trial data and the daily consumption of dry tea leaves TMDI = HR or STMR x Dry tea consumed daily The TMDI so computed is then compared with the Acceptable Daily Intake (ADI) per person, for a particular compound. However, this comparison of TMDI (so obtained) with ADI is actually a gross overestimation of potential risk to consumers as the dry tea leaves are never consumed raw. Such overestimation of risk will unduly eliminate useful pesticides

18 Risk assessment based on the brew factor The dietary risk assessment through consumption of tea liquor can therefore be assessed by incorporation of the brew factor in the intake calculations: TMDIb = HR or STMR x Dry tea consumed daily x Brew Factor where, TMDIb is Theoritical maximum Daily Intake based on Brew factor Use of Brew Factor will lower TMDI to actuals & prevent undue overestimation of risk Recent studies showed that the actual intakes of residues through tea consumption can be determined by incorporating this new parameter termed brew factor in the conventional estimates of TMDI. The compound specific brew factor improves risk assessment and will enable setting realistic maximum residue limits for pesticides in tea.

19 Illustrations on the use of brew factor for assessing risk from residues in teas Computation of MRL for Fenpyroximate in tea (For an Indian adult of 50kg weight) (ADI : 0.01 mg/kg bw) Pesticide Highest residues (HR) (mg/kg) Food consumpt ion (g) TMDI (mg/day) based on HR TMDI (mg/day) based on propose d MRL of 2 mg/kg ADI (mg/kg/ day) ADI per person (mg/day) % of ADI per person based on HR % of ADI per person based on proposed MRL Proposed MRL (mg/kg) Fenpyrox imate x 0.031* = x 0.031* = * [Brew Factor]

20 Illustration Computation of MRL for Indoxacarb in tea (For a Chinese adult of 60 kg weight) (ADI : 0.01 mg/kg bw) Pesticide Highest residues (HR) (mg/kg) Food consumpt ion (g) TMDI (mg/day) based on HR TMDI (mg/day) based on propose d MRL of 2 mg/kg ADI (mg/kg/ day) ADI per person (mg/day) % of ADI per person based on HR % of ADI per person based on proposed MRL Proposed MRL (mg/kg) Indoxaca rb x 0.062* = x 0.062*= * [Brew Factor]

21 Tea Brew preparation method Tea brew needs to be prepared using the dry tea leaves corresponding to the GAP PHI which is (7 days for tea) and following the standard of International Organization for Standardization (ISO) for organoleptic testing of teas for preparation of infusion. This involves extracting black/green/white tea leaves with boiling hot water (1:50=black tea : hot water ratio) for 5-6 min, partitioning the residues into an organic solvent (n-hexane ) and estimating the residues after concentration to suitable volumes.

22 Brew factor vrs Processing factor Brew factor has been defined earlier and denotes proportion of residues that can be transferred from dry tea leaves to tea brew, the form which is finally consumed. On the other hand the Processing factor refers to the proportion of residues in raw agricultural commodity (here freshly plucked tea shoots) to residues in dry tea leaves which has been obtained after processing the fresh tea shoots in factories. Since MRL is fixed on the dry tea leaves which is the traded commodity and only the tea brew (hot water extract) is consumed, the use of the term Brew Factor will be more relevant in case of tea than the term Processing Factor which may be applicable for other dry commodities directly consumed unlike tea. This explanation is expected to remove any confusion for those regulators or other users of this document who are not familiar with tea.

23 Determination of national estimates of risk using Brew factor Determination of any national estimates using the Brew factor for assessing actual risk from residues in tea can be made by suitable replacement of the following parameters in the Illustrations as applicable for a particular member country / region: (a) Daily Tea consumption (g/person/day) (b) Average adult body weight (kg) Determination of International Estimated of Daily Intakes (IEDI) or international estimated short term intake (IESTI) using brew factor Introducing the brew factor as an additional multiplication factor will refine these estimates as well by realistic proportioning of the contribution of residues from tea. The estimated amount will then be compared with the acute reference dose (ARfD)

24 Determination of International Estimated of Daily Intakes (IEDI) or international estimated short term intake (IESTI) using brew factor Introducing the brew factor as an additional multiplication factor will refine these estimates as well by realistic proportioning of the contribution of residues from tea. The estimated amount will then be compared with the acute reference dose (ARfD) The 13 GEMS/Food Consumption Cluster Diets [Ref: chem/countries.pdf] as well as the current 17 Cluster diets proposed in 2012 can also be suitably considered for brew factor based risk assessment for MRL fixation in tea. [Ref:

25 Advantage of assessing intakes with brew factors Overestimation of risk by conventional method as compared to risk assessment based on Brew Factor Bifenthrin Fenpropathin Cypermethrin Deltamethrin L-cyhalothrin Hexaconazole Propiconazole : 21 fold : 526 fold : 196 fold : 111 fold : 90 fold : 88 fold : 8 fold The brew factor will also help in both short and long term risk assessment to improve the estimate of intake of pesticide residues in tea as a reduction factor which was found to be compound specific. Slide 27/39 25

26 Benefit of Brew Factor MRL (Realistic) MRL (Unrealistic) Scope for upward revision of MRL without jeopardising Food Safety 26

27 FAO-IGG Ring Test (Black tea)-2014 Sample: Pesticides: Field treated black tea samples prepared at TRA, Tocklai, India Acetamiprid, Propiconazole, fenpyroximate & flubendiamide Water Solubility: High Medium Low Low No of participating laboratories : 14 Countries involved : China, India, Kenya, USA and Germany Date of dispatch of samples: Suggested method for extraction : Based on QUECHERS (AOAC) Suggested method for cleanup : d-spe Suggested method for estimation : LC-MS/MS Results submission : May 2014.

28 Action Plans 1. To generate pesticide residue data for fixation of MRLs in tea based on tea brew for more number of pesticides used in tea production. These information are recommended to be submitted to CCPR, JMPR and EU for MRL fixation. 2. As discussed and agreed in the CCPR Meeting, the MRLs for pesticides in tea would be set on the dried tea but the residues in the tea brew should be considered in the establishment of MRLs on dried tea. 3. The guidance document will be discussed in the IGG Meeting, and then submitted to the CCPR and JMPR for reference. 4. To review use of highly water soluble pesticides in tea as these are associated with greater risk to tea consumers.

29 Thank you