21ST SESSION OF FAO-IGG ON TEA, BANDUNG
05-07 NOVEMBER, 2014
REPORT OF THE
WORKING GROUP ON MRL IN TEA BREW
(2012-2014)
CHAIR: CHINA
CO-CHAIR : INDIA & USA
DR Y JIANG
DR 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
Way
to go
forward
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
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.
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)
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
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
Residues of pesticides (mg/kg) in black tea and in tea brew and Brew Factor
Pesticides
Rate of
application
In field
(kg·ai/ha)
Deltamethrin
0.0056
Bifenthrin
0.08
Fenpropathrin
0.03
Hexaconazole
0.05
Propiconazole
0.25
RBT
(mg/kg)
0.34
0.83
1.38
1.90
1.66
RTB
Brew
(mg/kg black Factor (BF)
tea used)
(RTB÷
RBT)
0.003
0.0090
0.038
0.0458
0.002
0.0019
0.022
0.0114
0.218
0.1315
Note: 1. RBT: Residues in black tea. 2. RTB: Residues in tea brew. [Adapted
Transfer into
brew
(BF×100)
(%)
0.90
4.58
0.19
1.14
13.15
from Barooah, et al, (2011)].
Residues of pesticides (mg/kg) in green tea and in tea brew and Brew Factor
Pesticides
Dimethoate
Imidacloprid
Acetamiprid
Tolfenpyrad
Indoxacarb
Fenitrothion
Malathion
Chlorfenapyr
Rate of
application
In field
(kg·ai/ha)
0.36
0.084
0.0225
0.122
0.05
0.203
0.405
0.045
RBT
(mg/kg)
1.34
1.07
5.46
8.93
1.85
1.27
7.76
2.55
RTB
Brew
(mg/kg black Factor (BF)
tea used)
(RTB÷
RBT)
1.32
0.983
0.3
0.28
4.64
0.85
0.018
0.002
0.115
0.062
0.96
0.756
6.70
0.863
0.0038
0.0015
Note: 1. RGT: Residues in green tea. 2. RTB: Residues in tea brew. [Adapted
Transfer into
brew
(BF×100)
(%)
98.3
28
85
0.2
6.2
75.6
86.3
0.15
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
TMDI
TMDI
ADI
ADI
% of
% of
Proposed
consumpt (mg/day) (mg/day) (mg/kg/
per
ADI per ADI per
MRL
based
based
ion
day)
person person
person
(mg/kg)
on HR
on
(mg/day)
(g)
based based on
propose
on HR proposed
d MRL
MRL
of
2 mg/kg
Fenpyrox
imate
1.78
10
0.0178
1.78
10
0.0178
0.05
x
x
0.031* 0.031*
=
=
0.00055 0.00155
2
0.05
* [Brew Factor]
0.01
0.5
3.56
10.0
5.0
0.01
0.5
0.11
0.31
5.0
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)
1.85
Food
TMDI
TMDI
ADI
ADI
% of
% of
Proposed
consumpt (mg/day) (mg/day) (mg/kg/
per
ADI per ADI per
MRL
based
based
ion
day)
person person
person
(mg/kg)
on HR
on
(mg/day)
(g)
based based on
propose
on HR proposed
d MRL
MRL
of
2 mg/kg
13
0.02405
13
0.02405
0.039x
x
0.062*=
0.062*
0.00248
=
1
0.00149
Indoxaca
rb
1.85
0.039
* [Brew Factor]
0.01
0.6
4.01
6.5
3
0.01
0.6
0.25
0.414
3
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
Slide 27/39
16
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 (Realistic)
Scope for upward revision of MRL
without jeopardising Food Safety
17
MRL (present system)
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, Germany
9. 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
TEST METHOD developed and provided with the samples
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.
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
26.5
Pesticides
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
FAO-IGG Global Ring test-2014 (Black Tea) Results for dry tea : Z-scores
Z-scores
Acetamiprid
2
Acetamiprid
1.5
√ [13/14 labs]
1
0.5
0
1
-0.5
2
3
4
5
6
7
8
9
10
11
12
13
-1
-1.5
-2
Flubendiamide
Flubendiamide
√ [12/14 labs]
3
2
1
0
-1
-2
1
2
3
4
5
6
7
8
9
10
11
-3
-4
-5
-6
Participating Laboratory’s Code numbers
12
13
FAO-IGG Global Ring test-2014 (Black Tea) Results for dry Tea : Z-scores
Fenpyroximate
Z-scores
2.5
Fenpyroximate
2
1.5
√ [12/14 labs]
1
0.5
0
-0.5
1
2
3
4
5
6
7
8
9
10
11
12
13
-1
-1.5
-2
Propiconazole
Propiconazole
2
1.5
√ [13/14 labs]
1
0.5
0
-0.5
1
2
3
4
5
6
7
8
9
10
11
-1
-1.5
-2
Participating Laboratory’s Code numbers
12
13
FAO-IGG Global Ring test-2014 (Black Tea) Results for tea Brew: Z-scores
Pesticides
Laboratories with satisfactory
Z-scores
Acetamiprid
13/14 labs
[-1.49 to +1.58]
Flubendiamide
11/14 labs
[-0.59 to +3.08]
Fenpyroximate
12/14 labs
[-0.66 to 2.88]
Propiconazole
13/14 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