Pesticide Residues in Food -reasons

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The slides shows glimpse of various pesticide which can creates residues

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  • these characteristicswere considered ideal for an insecticide ini-tially, they were soon found to be negativebecause of their persistence in the environ -ment,andtheirtendencytoaccumulateinthefood chain. Though not lethal, they directlyor indirectly affected the fertility and repro -ductionofmanywildspecies.Forthisreason,DDT and organochlorine compounds havebeen banned in agriculture since 1973 andheavily limited in the fight against thecarriers of diseases of mankind. Since themid-1980s, the use of DDT has been bannedin agriculture in all countries of the world.Aldrin, which degrades rapidly andforms its epoxide dieldrin by hydroxylation,is very stable in the environment. A half-lifeof 5 years in the soil has been calculated fordieldrin. Endrin is a stereoisomer of dieldrin.They are now used only in a very few specialcases such as the control of termites. Unlikethe other cyclodienes, endosulphan showsmoderate stability; in fruit and vegetables ittendstodegradeandformthecorrespondingsulphate with half-lives mostly rangingbetween 3 and 7 days.Hexachlorocyclohexane (HCH) mainlycontains four isomers ( α, β, γ and δ). Theisomer γ, lindane, which is the active isomer,has been isolated by crystallization from thisproduct.Lindaneistheleastpersistentamongthe organochlorine compounds.
  • Pesticide Residues in Food -reasons

    1. 1. Pesticide Residues in Food MOZHIARASU S M.Tech I Year,FSQM
    2. 2. Outline • Introduction- Definitions • Overview of different classes of pesticides • Factors influencing the residue formation • Risk Assessment & Monitoring Programmes on Pesticide Residues in Food
    3. 3. 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 Residues Any 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.
    4. 4. Toxicity LabellingLabel Name Level of toxicity Oral 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
    5. 5. Insectide • Classification by chemical group o Organo Chlorine o Organo Phosphate o Carbamates o Pyrethroids
    6. 6. 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 DDT Dicolfol Methoxychlor X-Cl Y=H X=Cl Y=OH X=OCH3 Y=H Aldrin Dialdrin & Endrin Endosulfan Lindane
    7. 7. 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−1BW Common 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
    8. 8. 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
    9. 9. Pyrethroids • Pyrethroids~ Pyrethrin (Tanacetum cinerariae- folium) Deltametrin- LD50 for the fly is 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
    10. 10. 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
    11. 11. Fungicides • Inorganic Fungicides- Copper Salts • Organic Fungicides in Table • DithiocarbomatesEthyl ene thio urea • Benzimidazoles- Systemic Fungicide • Dicarboximides- Resistant • Triazoles - biosynthesis of ergosterol • Anilinopyrimidines- Act on biosynthesis of AA Ref, Mello et al., 2003 : Food Safety: Comtaminants and toxins
    12. 12. 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
    13. 13. 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
    14. 14. Factors influencing in formation of Residues in Food • Disappearance rate o Environmental Factors o Crops o Enzymatic degradation o Washing • Initial deposit o Application rate o Formulation o Application techniques o Influence of cultivar o Shape of the cultivar
    15. 15. 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
    16. 16. Application techniques: • High Micronization in low volumes Influence of cultivar: Cabras et.al., 1997
    17. 17. Shape of the cultivar Cabras et.al., 1997
    18. 18. Disappearance Rate Environmental conditions • Washing • Evaporation, • Co-distillation • Photodegradti on
    19. 19. Crops Enzymatic Degradation
    20. 20. Washing- rain, washing or irrigation
    21. 21. 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,
    22. 22. 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 JMPR TOXICOLOGICAL 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
    23. 23. 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
    24. 24. INTERNATIONAL LEVEL
    25. 25. 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

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