21 st session of fao-igg on tea, bandung 05-07 november, 2014 report of the working group on mrl in...

21ST SESSION OF FAO-IGG ON TEA, BANDUNG05-07 NOVEMBER, 2014

REPORT OF THE WORKING GROUP ON MRL IN TEA BREW (2012-2014)

CHAIR: CHINA CO-CHAIR : INDIA & USA

DR Y JIANGDR A K BAROOAH MR PETER GOGGI JT COORDINATORS, WG ON TEA BREW

Background

In last Intersessional Meeting held in Rome on 5-6 May 2014,

Following action points were decided

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 44th 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 Session 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.

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)

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 with comments from USA and Japan.

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 in April 2014. Results were highly encouraging and validated the method for assessing residues in dry tea and tea brew.

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]

The Concept…….

Main Reason for opposition to fixing MRL in tea brew

Brew is not the commodity on sale

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

Way to go forward

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.

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

Definitions and terms used in this document

Black Tea: As defined in ISO 3720 (2011)Green Tea: As defined in ISO 11287 (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)

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

Tea shoots: Fresh green tea shoots comprising mostly 2 leaves and a bud, plucked to produce dry tea leaves.

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

Brew Factor = Residues in tea brew (mg/kg) ÷ Residues in dry tea leaves(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.

The residues in dry tea leaves are expressed in mg/kg.

Brew Factor has no units

Percent transfer of dry tea residues into tea liquor = Brew Factor x 100

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 0.0056 0.34 0.003 0.0090 0.90Bifenthrin 0.08 0.83 0.038 0.0458 4.58Fenpropathrin 0.03 1.38 0.002 0.0019 0.19Hexaconazole 0.05 1.90 0.022 0.0114 1.14Propiconazole 0.25 1.66 0.218 0.1315 13.15

Note: 1. RBT: Residues in black tea. 2. RTB: Residues in tea brew. [Adapted from Barooah, et al, (2011)].

Residues of pesticides (mg/kg) in black tea and in tea brew and Brew Factor

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 0.36 1.34 1.32 0.983 98.3Imidacloprid 0.084 1.07 0.3 0.28 28Acetamiprid 0.0225 5.46 4.64 0.85 85Tolfenpyrad 0.122 8.93 0.018 0.002 0.2Indoxacarb 0.05 1.85 0.115 0.062 6.2Fenitrothion 0.203 1.27 0.96 0.756 75.6Malathion 0.405 7.76 6.70 0.863 86.3Chlorfenapyr 0.045 2.55 0.0038 0.0015 0.15

Note: 1. RGT: Residues in green tea. 2. RTB: Residues in tea brew. [Adapted from Chen ZM et al, China].

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.

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

The compound specific brew factor improves risk assessment and will enable setting realistic maximum residue limits for pesticides in tea.

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 proposed MRL

of2 mg/kg

ADI(mg/kg/

day)

ADIper

person (mg/day)

% of ADI per personbased on HR

% of ADI per person

based on proposed

MRL

Proposed MRL

(mg/kg)

Fenpyroximate

1.78 10 0.0178 0.05 0.01 0.5 3.56 10.0 5.0

1.78 10 0.0178 x

0.031* =

0.000552

0.05x

0.031* =

0.00155

0.01 0.5 0.11 0.31 5.0

* [Brew Factor]

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 proposed MRL

of2 mg/kg

ADI(mg/kg/

day)

ADIper

person (mg/day)

% of ADI per personbased on HR

% of ADI per person

based on proposed

MRL

Proposed MRL

(mg/kg)

Indoxacarb

1.85 13 0.02405 0.039 0.01 0.6 4.01 6.5 3

1.85 13

0.02405x

0.062* =

0.00149

0.039x 0.062*=0.00248

1

0.01 0.6 0.25 0.414 3

* [Brew Factor]

Illustration

Overestimation of risk by conventional method as compared to risk assessment based on Brew Factor

Bifenthrin : 21 foldFenpropathin : 526 foldCypermethrin : 196 foldDeltamethrin : 111 foldL-cyhalothrin : 90 foldHexaconazole : 88 foldPropiconazole : 8 fold

16Slide 27/39

Advantage of assessing intakes with brew factors

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.

Benefit of Brew Factor

MRL (present system)

MRL (Realistic)

Scope for upward revision of MRLwithout jeopardising Food Safety

17

FAO-IGG Ring Test (Black tea)-2014

Sample: Field treated black tea samples prepared at TRA, Tocklai, India

Pesticides: 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: 04.04.2014

Suggested method for extraction : Based on QUECHERS (AOAC)

Suggested method for cleanup : d-SPE

Suggested method for estimation : LC-MS/MS

Results submission : June 2014.

Participating Labs in the FAO-IGG Ring Test-2014 (Black Tea)

1. TRI, Chinese Academy of Agricultural Sciences, China

2. Eurofins, Germany

3. Kenya Plant Health Inspectorate Service, Kenya

4. Eurofins Central Analytical Laboratories, USA

5. TLab, Tea Research Association, Kolkata, India

6. SGS INSTITUT FRESENIUS GmbH, Germany

7. TeeGschwendner GmbH, Germany

8. GALAB Laboratories GmbH, Germany9. PhytoLab GmbH & Co. KG, Germany

10. Wessling GmbH, Germany

11. PMA Peri Medizinische Analytik Sindelfingen GmbH, Germany

12. bilacon GmbH, Germany

13. GBA Gesellschaft für Bioanalytik mbH, Germany

14. TEEKANNE GmbH & Co. KG, Germany

Extraction with acetonitrile from the dry black tea leaves (rehydrated prior to extraction) and tea brew following a QUECHERS method & cleaned up by d-SPE & residues estimated by QQQ LC-MS/MS using matrix matched calibration standards.

TEST METHOD developed and provided with the samples

Pesticides Con (v) Q1 (m/z) CE (eV) Q2 (m/z)

CE (eV)

Acetamiprid

52 223>126

19 223>90 30.5

Flubendiamide

76 681>253.5

23.5 681>274

16.5

Propiconazole

84 342>159

29 342>69 16

TPP 104 327>152

32.5 327>215

26.5Pesticides Con

(v)Q1 (m/z)

CE (eV)

Q2 (m/z)

CE (eV)

Q3 (m/z)

CE (eV)

Fenpyroximate

84 422>366

16.0

422>135

32.0 422>138

33.0

TPP 104 327>152

32.5

327>215

26.5

Acetamiprid

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

1 2 3 4 5 6 7 8 9 10 11 12 13

FAO-IGG Global Ring test-2014 (Black Tea) Results for dry tea : Z-scores

Flubendiamide

-6

-5

-4

-3

-2

-1

0

1

2

3

1 2 3 4 5 6 7 8 9 10 11 12 13

Z-scores

Participating Laboratory’s Code numbers

Acetamiprid

Flubendiamide

√ [13/14 labs]

√ [12/14 labs]

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

1 2 3 4 5 6 7 8 9 10 11 12 13

Fenpyroximate

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

1 2 3 4 5 6 7 8 9 10 11 12 13

Propiconazole

FAO-IGG Global Ring test-2014 (Black Tea) Results for dry Tea : Z-scores

Z-scores

Fenpyroximate

√ [12/14 labs]

Propiconazole

√ [13/14 labs]

Participating Laboratory’s Code numbers

FAO-IGG Global Ring test-2014 (Black Tea) Results for tea Brew: Z-scores

PesticidesLaboratories with satisfactory

Z-scores

Acetamiprid13/14 labs

[-1.49 to +1.58]

Flubendiamide11/14 labs

[-0.59 to +3.08]

Fenpyroximate12/14 labs

[-0.66 to 2.88]

Propiconazole13/14 labs

[-2.04 to 1.91]

Results validated the method developed by Tlabs, India for testing tea & brew

It addressed the issue on lack of method for risk assessment

Action Plans

1. To generate pesticide residue data for fixation of MRLs in tea based on risk assessment in 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 21st IGG session, 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.

5. Having completed its tasks and after acceptance of the document, the WG will be dissolved.

Thank you