Pesticide Residues in Food -reasons

Pesticide Residues in

FoodMOZHIARASU S

M.Tech I Year,FSQM

Outline• Introduction- Definitions• Overview of different classes of pesticides• Factors influencing the residue formation• Risk Assessment & Monitoring Programmes on

Pesticide Residues in Food

Pesticide & Residues- Definitions

• Biocide by definition is any substance used with the intention of killing living organisms whether these are pests or not.

• Pesticides are compounds that man uses to control, meaning to reduce in number or to eradicate, organisms that interact negatively with his activities such as crop production and gardening, or to control disease in people, animals, etc.

• Pesticide ResiduesAny substance or mixture of substances in food for man or animals resulting from the use of a pesticide including any specified derivatives, such as degradation and conversion products, metabolites, reaction products and impurities considered to be of toxicological significance.

Toxicity LabellingLabel Name Level of

toxicityOral lethal dose mg per kg body weight of test

animal

Listed chemicals

Red label Extremely toxic

1-50 Monocrotophos, zinc phosphide, ethyl mercury acetate, and others.

Yellow label

Highly toxic 51-500 Endosulfan, carbaryl,quinalphos, and others.

Blue label Moderately toxic

501-5000 Malathion, thiram,glyphosate, and others.

Green label

Slightly toxic

More than 5000 Mancozeb, oxyfluorfen, mosquito repellant oils and liquids, and most other household insecticides.

Wikipedia

Insectide• Classification by chemical group

o Organo Chlorineo Organo Phosphateo Carbamateso Pyrethroids

Organochlorine• Organic compound containing at least one covalently

bonded atom of chlorine (the diphenylethanes, the cyclodienes and the Cyclohexanes)- Highly Effective against various Insects

• High persistence and Highly lipophilic

DDTDicolfol

Methoxychlor X-Cl Y=H

X=Cl Y=OHX=OCH3 Y=H

Aldrin Dialdrin & Endrin

Endosulfan Lindane

Organophosphate• acetylcholinesterase (AChE) in ganglia and in the parasympathetic

nervous system. [SLUD Syndrome]• Highly Toxic , Less lipophilicity, Fast degradation• Parathion (parathion-ethyl) introduced in 1944 -higher

environmental stability LD 50:3–13 mg kg−1BWCommon name Rat oral LD50 Rabbit dermal LD50

Chlorpyrifos 96–270 2,000

Diazinon 1,250 2,020

Dimethoate 235 400

Ethoprop 61.5 2.4

Fenamiphos 10.6–24.8 71.5–75.7

Malathion 5,500 >2,000

Methamidophos 13 (female only) 122

Methyl parathion 6 45

Ref,Mello et al., 2003 : Food Safety: Comtaminants and toxins

Carbamates• Low toxicity/ Low Lipophilic • Acetylcholineesterase

Inhibitor (Reversable)

Common name Rat oral LD50 Rabbit dermal LD50

Aldicarb 1 20

Carbaryl 500–850 >2,000

Carbofuran 8 >3,000

Fenoxycarb 16,800 >2,000

Methiocarb 60–1,000 depending on product >2,000 (rat)

Methomyl 30–34 >2,000

Oxamyl 5.4 2,960

Thiodicarb 66 >2,000

Pyrethroids• Pyrethroids~ Pyrethrin (Tanacetum cinerariae-

folium)

Deltametrin-LD50 for the flyis 0.0003 µg

Common name Rat oral LD50 Rabbit dermal LD50

Allethrin 860 11,332

Bifenthrin 375 >2,000

Cyfluthrin 869–1271 >5,000 (rat)

Cyhalothrin 79 632 (rat)

Cypermethrin 250 >2,000

Deltamethrin 31–139 (female) >2,000

Esfenvalerate 451 2,500

Fenpropathrin 70.6–164 >2,000

Fluvalinate 261–282 >20,000

Permethrin 430–4,000 >2,000

Benzoylureas• Synthesized between dichlobenil derivatives and

fenuron• Act on the formation of chitin,hindering the

development of larvae during moult (by causing the imperfect formationof the new cuticle) and causing their death.

• They are not selective , affect CNS of mammals.• Eg., Diflubenzuron, Flufenoxuron, Hexaflumuron

Fungicides• Inorganic Fungicides-

Copper Salts• Organic Fungicides in

Table• DithiocarbomatesEthyle

ne thio urea• Benzimidazoles- Systemic

Fungicide• Dicarboximides- Resistant• Triazoles - biosynthesis of

ergosterol• Anilinopyrimidines- Act on

biosynthesis of AARef,Mello et al., 2003 : Food Safety: Comtaminants and toxins

Herbicides• mechanism of action of

herbicides is an interaction with the biochemical processes of vegetables, they have no toxicity for animals, But

• Dermitis• Paraquat- Toxic to lungs• Percolate into soil

Ref,Mello et al., 2003 : Food Safety: Comtaminants and toxins

Formulation of Pesticides

WHY WE NEED FORMULATION?• Active Ingredient (AI)

shows activity at low doses• Even Distribution• Easy and safe distribution

TYPES OF FORMULATION• Wettable powders• Emulsifiable concentrates• Granules• Flowable powders• Microcapsules

Points to remember:• Dose Precision• Contaminants

COMPOUNDS USED IN FORMULATION:• Adhesive Agent• Anti Evaporative Agents• Diluents for solids• Dispersants

Penetrants• Solvents• Surfactants

Ref,Mello et al., 2003 : Food Safety: Comtaminants and toxins

Factors influencing in formation

of Residues in Food• Disappearance rate

o Environmental Factorso Cropso Enzymatic degradationo Washing

• Initial deposito Application rateo Formulationo Application techniqueso Influence of cultivaro Shape of the cultivar

Initial Deposit• Application rate(Per Hectare): 1st Generation –

1kg/, 2nd Generation – few Hundred Grams, Last Generation- Few tens of grams

• Formulation: If granules gives progressive absorption and a distribution effect

Cabras et.al., 1999

Application techniques:• High Micronization in low volumes

Influence of cultivar:

Cabras et.al., 1997

Shape of the cultivar

Cabras et.al., 1997

Disappearance RateEnvironmental conditions• Washing• Evaporation

, • Co-

distillation• Photodegra

dtion

Crops

Enzymatic Degradation

Washing- rain, washing or irrigation

Residues in Processing of Foods: • 1 l of wine is obtained from 1.5 kg of grapes,• 1 l ofolive oil from 5 kg of olives• 1 kg of dried prunes from 3 kg of plums,

Risk Assessment & Monitoring Programmes on

Pesticide Residues in Food• Maximum Residue Limit (MRL)- maximum concentration of a

pesticide residue (expressed as mg/kg) that the CAC recommends be legally permitted in food commodities and animal feeds

• MRLs recommended by the JMPRTOXICOLOGICAL DOSSIER:• ADI (Accetable Daily Intake) derived from biochemical,

metabolic, pharmacological, and toxicological properties of the pesticide derived from studies of experimental animals and observations in humans.

• no-observed-adverse-effect level (NOAEL)ADI= NOAEL/Safety Factor (10 to 1000)

ENVIRONMENTAL DOSIER:• predicting pesticide residue intake include the residue levels

found in practice, their distribution in the commodity, and the effect on residues of the various processes used in the preparation of food

Exposure assessment:Exposure to a pesticide residue present, or likely to be present

under GAP should be less than ADI

Risk characterization:• Theoretical Maximum Daily Intake (TMDI) is used as a convenient

screening tool for assessing dietary intake• the International Estimated Daily Intake (IEDI) is used to obtain a

better estimate of dietary exposure.• TMDI and IEDI, the risk characterization is based on an average

adult weighing 60 kg

Ref,Guidelines for predicting dietary intake of pesticide residues, WHO Publication

INTERNATIONAL LEVEL

National Level

National Estimated Daily Intake differs from IEDI by• Proportion of crop or commodity treated• Proportions of crop or commodity produced domestically and imported• Monitoring and surveillance data• Total diet studies

THANKS