Pesticide residues

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2. What is pesticide residues ?
When a crop is treated with a pesticide, a very small
amount of the pesticide, or its metabolites or
degradation products, can remain in the crop until
after it is harvested.
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3. why do they turn up in our food?
to control the growth of weeds
– used by farmers
or prevent crop damage by insects, rodents and molds.
– used on food crops after harvest to prolong their storage life.
– used on animal farms to control insect pests
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4. HARMFUL EFFECTS OF PESTICIDE
RESIDUES To the Environment
 water systems
 Pollute the air.
insect species
 Harming beneficial soil microorganisms
worms
 Weakening plant root systems and immune systems.
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5. Do Processed Foods Have Less
Pesticides Than Fresh Foods?
 Generally, yes.
 Reason:
 Growers : don’t need to ensure that their foods are cosmetically perfect
 Processors : consumer demand for foods with minimal pesticide residues
 Processing : reduce pesticide residues
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6. EFFECT OF PROCESSING ON
PESTICIDE RESIDUES
Reduce
pesticide
residues
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7. METHODS USE TO REMOVE PESTICIDE
RESIDUES.
 Washing
 Peeling
 Hulling
 Trimming
 Cooking + Stir-frying
 Canning
 Freezing
 Drying
 Infusion
 Parboiling
 Storage
 Chemical solution
 Neutral solutions
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8. Washing
 Surface residues simple washing operations
 systemic residues present in tissues will be little affected
 the proportion of residue that can be removed by washing declines with time
 Hot washing and blanching cold washing
 commercial washing Domestic rinsing
 EX:
Washing rice grains with water removed approximately 60% of the chlorpyrifos residues
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9.  Washing+ cooking: apple to sauce 98%
 Washing and drying
 Washing and peeling
 Washing, peeling and juicing
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10. the effectiveness of washing in removing residues depends upon
four factors
 the location of the residue
 the age of the residue
 the water solubility
 the temperature
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11. Peeling
 residues are confined to the outer surfaces removal in peeling, hulling or trimming operations
 Peeling fresh fruits such achieves virtually complete removal of residues from the fruit.
 avocado
 bananas
 citrus
 kiwifruit
 mango
 Pineapple
 Peeling methods:
 Chemical peeling (mostly lye peeling)
 mechanical peeling (mainly abrasion peeling),
 steam peeling
 freeze peeling
 Residues of systemic pesticides can enter the flesh of crop!
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12. Peeling and cooking
 Peeling + blanching affect organophosphorous organochlorine
 Peeling + frying
 Reason: stability of organochlorines to heat treatment
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13. Hulling
 The hulls of cereal grains generally contain the
majority of pesticide residues from any field
treatments.
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14. Trimming
 removal of either inedible parts or parts with defects,
or for cutting the raw material to a size that is suitable
for further processing.
 Ex:
 Pirimiphos methyl residues in rice were reduced 70 percent and 90 percent by husking and polishing,
respectively
 Husking of corn (maize) removed 99 percent of the residues from field treatments with tetrachlorvinphos
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15. Cooking and canning
 Pesticide residues depend on:
 time
 temperature
 degree of moisture loss
 whether the system is open or closed
 the heat degradation and volatilization of residues
 EX:
Only 13 percent of parathion residues on tomatoes were found in canned juice or ketchup.
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16. Stir-frying
 Pesticide residues can be effectively decreased by stir-frying
 These can be reduced upto 49 and 53 percent by peeling and frying
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17. freezing
 Freezing : slows food decay
slow most chemical reactions
 EX
 Freezing of tomatoes decreased the pesticide residues from 5 to 26 percent after
six days and 10 to 31 percent after 12 days of pesticide contamination
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18. Drying
 Drying has been found to reduce the pesticide residues considerably.
 EX:
 Sunlight drying lead to around 50% decline in bitertanol residues from 0.50 ppm present at harvest
 Drying of grapes lead to 64.2–71.9% losses of methamidophos possibly due to evaporation of the
pesticide during the process
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19. infusion
 Tea: 64% processing…….. 36%remain........... 16%of the pesticide is transferred to cup-infusion
 The transfer of quinalphos to the infusion could be due to its solubility in water
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20. Parboiling
 means precooking of rice within the husk.
 Parboiling : hydrating padd + heating to cook the rice + drying of the rice
 high temperature (100 C)…. inactivation or degradation of pesticides
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21. Storage
long term (3–36 months)
 Grains stored at ambient temperatures
in bulk silos
 insecticides may be applied post-harvest to reduce losses from storage pests.
 pesticides can migrate through to the bran and germ
 Storage + milling Reduced pesticide residues
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22. EFFECT OF CHEMICAL SOLUTIONS
ON PESTICIDE RESIDUES
 Acidic solutions
citric acid
acidic solution ascorbic acid
acetic acid
hydrogen peroxide
 at a concentration of 5 and 10 percent for 10 minutes reduction of pesticide residues.
 Acidic solutions neutral and alkaline solutions
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23. Alkaline solution
 Solutions of NaOH, acetic acid, potassium dichromate
 Dipping of fruits in NaOH solution removed 50 to 60 percent surface residues of pyrethroids
compared to 40 to 50 percent removal by hydrolytic degradation with NaOH and a
detergent solution removed 50 to 60 percent residues omate and soap are used as
decontaminating agents
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24. Ozonation
 Ozone because of its powerful oxidizing property is effectively applied in drinking
water and waste water treatment
 Tap water treatment + ozonated water treatments significantly reduced the
pesticide residues on vegetables, as compared to no-wash treatment
pesticide residues
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25. Neutral solutions
 Sodium chloride (NaCl) solution
28 to 93% organochlorines
100 % organophoshates
NaCl concentration pesticide residues
5 and 10 % NaCl
solution for 15 minutes
rubbed by hand
water was decanted
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26. What Can You Do?
 Grow some of your food using organic methods.
 Buy organic food.
 Wash and scrub all fresh fruits, vegetables
 Eat less or no meat.
 Trim the fat from meat.
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27. References:
1)Ahmed, A., Randhawa, M. A., Yusuf, M. J., & Khalid, N. (2011). EFFECT OF
PROCESSING ON PESTICIDE RESIDUES IN FOOD CROPS-A REVIEW.Journal of
Agricultural Research, 49(3).
2) Holland, P. T., Hamilton, D., Ohlin, B., & Skidmore, M. W. (1994). Effects of storage
and processing on pesticide residues in plant products. Pure and Applied Chemistry,
66(2), 335-356.
3) Krieger, R. I., Brutsche-Keiper, P., Crosby, H. R., & Krieger, A. D. (2003). Reduction of
pesticide residues of fruit using water only or plus Fit™ Fruit and Vegetable Wash.
Bulletin of environmental contamination and toxicology, 70(2), 0213-0218.
4) Hyder, K. (2006). GMP and HACCP for tree nuts and dried fruit processing plants in
Afghanistan. Submitted to: USAID Prime Contractor: Chemonics International Inc.,
Rebuilding Agricultural Markets Program (RAMP). p, 1-17.
5) Pandey, P., Raizada, R. B., & Srivastava, L. P. (2010). Level of organochlorine
pesticide residues in dry fruit nuts. Journal of Environmental Biology, 31(5).
6) Kaushik, G., Satya, S., & Naik, S. N. (2009). Food processing a tool to pesticide
residue dissipation–A review. Food Research International, 42(1), 26-40.
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