Presentation during the Bureau of Agricultural Research (BAR) Seminar Series on June 23, 2016 at RDMIC Bldg., cor. Visayas Ave., Elliptical Rd., Diliman, Quezon City

1. DIETARY RISK ASSESSMENT OF INSECTICIDE
RESIDUES IN FRESH SALAD VEGETABLES
SUSAN MAY F. CALUMPANG
National Crop Protection Center
University of the Philippines Los Baños
6/23/2016SMF CALUMPANG ISSAAS 2015
1

2.  Insect pest pressure in vegetable production is
very intense.
 So many insect pests, so farmers use insecticides.
 Thus, farmers spray every 2-3 days or even worse
spray in the late afternoon and harvest early the
next day.
 Mixing or cocktailing of insecticides is also
practiced by some farmers.
 Thus, pesticide use must be managed.
Pest management problems in the field
2

3. SMF CALUMPANG
Good agricultural practice includes:
1.Food safety
2.Food quality
3.Environmental management
4.Worker health, safety and welfare
Vegetable production is a difficult situation to follow
good agricultural practice, pre-harvest intervals in
particular.
Some vegetable farmers will not observe pre-harvest
interval.
3

4. Monitoring of insecticide residues in
fresh salad vegetables was conducted
using market basket sampling from
2014 to 2015.
Fresh vegetables included lettuce,
carrots, tomato, cucumber, celery as
well as various sprouts.
Sampled from supermarkets in the
Metro Manila area and Laguna,
Philippines.
6/23/2016SMF CALUMPANG ISSAAS 2015
4

5. Commercial salad mixes and
sprouts were also sampled from fast
food chains and supermarkets in the
Metro Manila area and Laguna,
Philippines. Commercial salads
Tom Yao, Alfalfa and Mung bean sprouts
6/23/2016SMF CALUMPANG ISSAAS 2015
5

6. Fresh vegetable samples were blended,
laboratory sample weighed, and frozen.
Insecticide residues were extracted and
partitioned using organic solvent, clean-up
with SPE cartridges and concentrated in a
rotary evaporator.
Analysis by gas chromatography
6/23/2016SMF CALUMPANG ISSAAS 2015
6

7. How can we reduce insecticide residue
levels in vegetables?
Washing with mild detergent
and grilling of eggplant
(without peeling)
Washing with mild
detergent and boiling of
tomato and pechay
6/23/2016SMF CALUMPANG ISSAAS 2015
7

8. MARKET BASKET SURVEY
6/23/2016SMF CALUMPANG ISSAAS 2015
8

9. MUNGBEAN SPROUTS (10), TOMATO (9), CUCUMBER (5)
DID NOT CONTAIN ANY DETECTABLE RESIDUES.
6/23/2016SMF CALUMPANG ISSAAS 2015
9

10. In general, celery had the most detections (85% of 13 samples)
• Chlorpyrifos residues ranged from 0.4 to 45 ppb (ug/kg)
• The highest residue represents 1.6% of the Acceptable Daily
Intake (0.01 mg/kg body weight) for a consumption of 200 g
celery per day
• Highest profenofos residues= 0.07 ppm
• Represents 0.3% of the ADI (0.1 mg/kg body weight)
6/23/2016SMF CALUMPANG ISSAAS 2015
10

11. 1074
A popular commercial fresh garden salad contained
very low levels of organophosphate insecticide residues,
such as: Chlorpyrifos, profenofos and diazinon
Chlorypyrifos residues detected: 85% of 14 samples
Profenofos residues detected: 43% of samples
6/23/2016SMF CALUMPANG ISSAAS 2015
11

12. 6/23/2016SMF CALUMPANG ISSAAS 2015
12
Fresh Garden Salad:
Chlorpyrifos residues ranged from 0.2 to 21.4 ppb
(lower than celery)
The highest residue represents 0.8% of the
Acceptable Daily Intake (0.01 mg/kg body weight)
for a consumption of 200 g fresh salad per day
Highest profenofos residues= 0.01 ppm
Represents 10% of the ADI (0.1 mg/kg body weight)

13. LETTUCE (11 SPLS) - 3 DETECTIONS
6/23/2016SMF CALUMPANG ISSAAS 2015
13
Chlorpyrifos residues, 1.67 to 2.6 x 10-4 ppm
Diazinon, 3.3 to 3.5 x 10-4 ppm
Highest chlorpyrifos residue = 0.009% of its Acceptable Daily Intake
(0.01 mg/kg body weight) for a consumption of 200 g lettuce per day
Diazinon residues = 0.06% of diazinon ADI (0.002 mg/kg bw)

14. 6/23/2016SMF CALUMPANG ISSAAS 2015
14
Monitoring data indicates the need for :
1. Increased monitoring efforts to check
compliance to label information, such
as pesticide-free or organic vegetables
2. Need for less expensive method for
pesticide residue analysis and/or
portable sensors to facilitate monitoring
activities

15. 6/23/2016SMF CALUMPANG ISSAAS 2015
15
How can we reduce insecticide
residue levels in vegetables?

16. Home processing
Profenofos Chlorpyrifos
Residues
mg/kg
Percent
Reduction
Residues
mg/kg
Percent
Reduction
1. Unwashed 0.61 0.12
2. Unwashed, boiled 0.08 86.8 0.031 73.5
3. Unwashed, grilled 0.22 67.0 0.027 76.9
4. Washed, running water 0.14 76.9 0.097 17.1
5. Washed, 0.5% powder
detergent
0.10 83.5 0.10 14.7
6. Washed, 0.02 % liquid
detergent rinse
0.04 66.7
EFFECT OF HOME PROCESSING ON INSECTICIDE
RESIDUE LEVELS - EGGPLANT
6/23/2016SMF CALUMPANG ISSAAS 2015
16

17. EFFECT OF HOME PROCESSING ON INSECTICIDE
RESIDUE LEVELS - PECHAY
6/23/2016
17
Home processing
Chlorpyrifos
Residues
mg/kg
Percent
Reduction
1. Unwashed 23. 27 -
2. Unwashed, boiled 30.06 + 29
3. Washed, running water 21.48 8
4. Washed, 0.5% powder detergent 20.69 11
5. Washed, 0.02% liquid detergent 12.9 44
Chlorpyrifos is thermally stable thus reduction on boiling is not
significant.

18. 6/23/2016SMF CALUMPANG ISSAAS 2015
18
Home food processing of vegetables, such as
washing with water, mild detergent, boiling and
grilling can reduce some organophosphate
insecticide residues in vegetables.
This reduces the dietary risk in the consumption of
fresh salad vegetables.

19. 6/23/2016SMF CALUMPANG ISSAAS 2015
19

20. 6/23/2016SMF CALUMPANG ISSAAS 2015
20

21. 6/23/2016SMF CALUMPANG ISSAAS 2015
21

22. 6/23/2016SMF CALUMPANG ISSAAS 2015
22
Thank you!

23. 6/23/2016SMF CALUMPANG ISSAAS 2015
23
In general, celery had the most detections (85% of 13 samples)
• Chlorpyrifos residues ranged from 0.4 to 45 ppb (ug/kg)
• The highest residue represents 1.6% of the Acceptable Daily
Intake (0.01 mg/kg body weight) for a consumption of 200 g
celery per day
• Consumption:
• 0.2 kg x 45 ug/kg = 9 ug chlorpyrifos consumed
• 9 ug = 0.16 ug = 0.00016 mg chlorpyrifos/kg bw
• 55 kg bw kg bw
• 1.6% of the Acceptable Daily Intake (0.01 mg/kg body
weight)