The effect of different household washing methods on removing lambda-cyhalothrin pesticide residues from tomatoes

The effect of different household washing methods on removing lambda-cyhalothrin pesticide residues from tomatoes | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The effect of different household washing methods on removing lambda-cyhalothrin pesticide residues from tomatoes Mohammed AbdAlbagi Osman, Mohammed Mobark Awad, Lubna ELfatih Khidir This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7272923/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study investigated the presence of residues of the pesticide lambda-cyhalothrin and its behavior with different washing treatments in tomato samples using gas chromatography-tandem mass spectrometry (GC-MS/MS) technique. Ten tomato samples were subjected to different household washing treatments (tap water, 10% sodium chloride solution, 20% vinegar-water solution (1:4), followed by extraction and analysis of the pesticide using the QuEChERS technique. Residue levels varied by treatment, with the unwashed sample having a concentration of 104.00ppb, with a 00.0% removal rate. The samples were as follows: (92.09, 88.66, 87.85, 100.71, 99.75, 92.84, 103.16, 97.47, 94.33)ppb and (11.45, 14.75, 15.52, 3.16, 4.09, 10.73, 0.81, 6.28, 930)% respectively. Washing with tap water only for 15 minutes achieved the highest removal rate of tomatoes, with a percentage of (15.52%) while washing with20% vinegar-water solution (1:4), for 5 minutes recorded the lowest removal rate, with a percentage of (0.81%). This study confirms that lambda-cyhalothrin residues in tomatoes can be significantly reduced through appropriate washing techniques. The study recommended that consumers follow these practices to reduce the risk of dietary exposure to pesticide residues. It also recommended that the effect of other food processing methods, such as cooking or peeling, on pesticide residue levels be studied. Public awareness should also be raised about effective washing techniques. Future research should assess the cumulative risks of pesticide residues in In the soil, in the fruit, and in the human body. Pesticides Pesticide residues Lambda-cyhalothrin Tomatoes Household washing Figures Figure 1 Introduction Food is the sole means of sustaining life for humans and all living organisms. Food is any substance eaten or drunk to provide nutritional support for the body, or for enjoyment. Given the increasing variety of foods—fresh, processed, and preserved—the need for knowledge of various food preservation methods and agricultural pest control methods is growing, starting from the planting stage, then harvesting, through the various stages of manufacturing, and finally the final product. Pesticides are substances that are meant to control pests, including weeds. The term pesticide includes all of the following : herbicide, insecticides (which may include insect growth regulators, termiticides, etc.) nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent animal repellent, antimicrobial, fungicide, disinfectant (antimicrobial), and sanitizer. (Randaall, 2014) The most common of these are herbicides which account for approximately 80% of all pesticide use. Most pesticides are intended to serve as plant protection products (also known as crop protection products). Pesticides can be classified based upon their biological mechanism function or application method. Most pesticides work by poisoning pests. (pesticide applicator, 2018). which in general, protect plants from weeds, fungi, or insects. Pesticides are essential to modern agriculture, but their residues in food raise health and environmental concerns (Akter et al., 2009, p. 34). Lambda-cyhalothrin is a synthetic pyrethroid insecticide widely used in agricultural practices to control a variety of pests, particularly on vegetable and fruit crops such as tomatoes. Its effectiveness in controlling pests, coupled with its relatively low application rates, has made it a popular choice among farmers. It is broadly effective against various insect pests (Tomlin, 2006, p. 188). However, due to its chemical stability and potential health effects, lambda-cyhalothrin residues may remain in food products after harvest, raising concerns about food safety. Exposure to high levels of this pesticide can affect the nervous system, prompting regulatory agencies to establish maximum residue limits (MRLs) for various foodstuffs. Its persistent presence on crops such as tomatoes makes monitoring residue levels crucial to ensuring food safety (FAO, 2021, p. 52). Materials and Methods Detailed Analytical Procedures 1. Sample Collection and Washing Treatments: Fresh tomato samples were randomly collected from Sadat City Market in Egypt, where different samples were collected. The samples were sprayed with lambda-cyhalothrin according to the pesticide spray specifications printed on the pesticide package. The samples were placed under natural conditions to simulate field conditions. The samples were washed approximately 18 hours after the pesticide spray to ensure that the pesticide remained on the surface of the samples and did not degrade rapidly. Sample extraction followed the QuEChERS method. The samples were analyzed for lambda-cyhalothrin residues using gas chromatography-mass spectrometry/mass spectrometry techniques. Sample Number and Washing Procedures: The experiment was conducted using 10 independent tomato samples. Each sample was subjected to one of the following washing treatments: Sample code treatment 1 No wash (control group) for 0 minutes. 2 Tap water for 5 minutes. 3 Tap water for 10 minutes. 4 Tap water for 15 minutes. 5 Saline solution (10% sodium chloride) for 5 minutes. 6 Saline solution (10% sodium chloride) for 10 minutes. 7 Saline solution (10% sodium chloride) for 15 minutes. 8 Water and vinegar solution (1 water : 4 vinegar) for 5 minutes. 9 Water and vinegar solution (1 water : 4 vinegar) for 10 minutes. 10 Water and vinegar solution (1 water : 4 vinegar) for 15 minutes. Tomatoes were manually mashed and stirred to simulate common household practices. After washing, samples were homogenized using a stainless steel grinder. Sample extraction and cleanup followed the EN 15662 QuEChERS protocol (CEN, 2008): Samples were processed and analyzed using the QuEChERS extraction method, followed by GC-MS/MS analysis. 2. Sample Homogenization - Homogenize the washed samples using a stainless steel blender. - Transfer them to sterile containers. 3. Extraction using EN 15662 QuEChERS standard Materials: • Acetonitrile (HPLC grade) • Magnesium sulfate, sodium chloride, sodium citrate dihydrate, disodium hydrogen citrate Method: - Weigh 10 grams of homogenized tomatoes into a 50 ml centrifuge tube. - Add 10 ml of acetonitrile and shake for 1 minute. - Add 4 grams of magnesium sulfate, 1 g of sodium chloride, 1 g of sodium citrate dihydrate, and 0.5 g of sodium hydroxide citrate dihydrate. - Shake immediately, then centrifuge at 3500-4000 rpm for 5 minutes. 4. Clean-up (d-SPE) Materials: • 150 mg PSA, 150 mg C18, 900 mg MgSO₄ Procedure: - Transfer 6 ml of the supernatant to a 15 ml d-SPE tube. - Stir for 30 seconds, then centrifuge at 12,000 rpm for 5 minutes. 5. Filtration and GC-MS/MS Analysis - Extract by filtration using a 0.22 µm PTFE syringe filter into GC-MS/MS vials. GC-MS/MS Parameters: • Column: HP-5ms (30 m × 0.25 mm × 0.25 µm) • Carrier gas: Helium, 1 mL/min • Injection: Splitless, 1 µL volume, 250°C • Oven: 70°C (1 minute), then increase the temperature to 150°C (25°C/min), then to 280°C (5°C/min), then hold for 5 minutes • Mode: MRM transitions for lambda-cyhalothrin • Tomato samples (3 kg each) were randomly collected from local markets. • Each sample underwent a specific washing process: rinsing with tap water, washing with a 10% saline solution, or washing with a vinegar solution (1:4). Washing times ranged from 5, 10, and 15 minutes, depending on the sample type. Each tomato batch was placed in a plastic container and manually stirred to simulate traditional household cleaning. After treatment, the samples were filtered, and residues were extracted. Analytical measurements were performed using gas chromatography-mass spectrometry (GC-MS/MS) according to standard laboratory pesticide residue protocols. All post-treatment concentrations were recorded for individual analysis. After washing, each tomato sample was homogenized using a laboratory grinder. Pesticide residues were extracted using the European method: EN 15662 (QuEChERS). This method involves extracting the analytes with acetonitrile, followed by partitioning with magnesium sulfate and sodium chloride. Clean-up was performed using dispersive solid-phase extraction (d-SPE) with primary secondary amine (PSA) and additional sorbents. The purified extract was filtered and injected into a gas chromatography-mass spectrometry (GC-MS/MS) system to quantify lambda-cyhalothrin residues according to the European guidelines for pesticide residues. The sample was extracted and cleaned up according to the European standard method EN 15662 (QuEChERS) (European Committee for Standardization, (CEN) 2008): a representative sample (10 g) was weighed into a 50 ml centrifuge tube. 10 ml of acetonitrile (MeCN) was added, and the mixture was shaken vigorously for 1 min. A buffer salt mixture containing: 4 g of anhydrous magnesium sulfate (MgSO₄), 1 g of sodium chloride (NaCl), 1 g of trisodium citrate dihydrate (Na₃C₆H₅O₇ 2H₂O), and 0.5 g of disodium hydrogen citrate hemihydrate (Na₂HC₆H₅O₇ 1.5H₂O) was added. The tube was shaken and centrifuged at 3000–4000 rpm for 5 min. Then, 6 mL of the upper liquid was transferred to a 15 mL d-SPE tube contained 150 mg of PSA, 150 mg of C18, and 900 mg of MgSO₄. After mixing for 30 seconds and centrifuging again, the extract was filtered through a 0.22 µm PTFE filter and analyzed using GC-MS/MS. Results The table below show the percentages of remaining concentrations after washing with different detergents. Sample code Conc/ppb Percentage of pesticide removal 1 104.00 00.00% 2 92.09 11.45% 3 88.66 14.75% 4 87.85 15.52% 5 100.71 3.16% 6 99.75 4.09% 7 92.84 10.73% 8 103.16 0.81% 9 97.47 6.28% 10 94.33 9.30% The figure below show the percentages of remaining concentrations after washing with different detergents. Discussion The results showed the presence of lambda-cyhalothrin residues in tomatoes, even after washing them using different methods, using different materials, and for different periods of time. However, washing with water significantly reduced these residues, removing 11–15% within 5–15 minutes. Pesticide removal using a 10% saline solution ranged from 3–10% within 5–15 minutes, while pesticide removal using water and vinegar ( 1 – 4 ) ranged from 0.8–9% within 5–15 minutes. The results showed that treating tomatoes sprayed with lambda-cyhalothrin, whether by washing them with tap water, salt water, or vinegar water for different periods of time, removed the pesticide residues. Conclusion This study confirms the potential for significantly reducing lambda-cyhalothrin residues in tomatoes through appropriate washing techniques, which have been proven effective in experiments. Washing with tap water alone for 15 minutes achieved the highest pesticide removal rate from tomatoes,15.52%. The results showed the presence of lambda-cyhalothrin residues in tomatoes, even after washing them with different methods and materials, and for different periods of time. However, washing with water resulted in a significant reduction in these residues, removing 11–15% within 5–15 minutes. Pesticide removal using a 10% saline solution ranged from 3–10% within 5–15 minutes, while pesticide removal using water and vinegar (1:4) ranged from 0.8-9% within 5–15 minutes. The results showed that treating tomatoes sprayed with lambda-cyhalothrin, whether by washing them with tap water, salt water, or vinegar water for different periods of time, removed a portion of the pesticide residues. decomposition or cooking. Recommendations The study recommends the following: Consumers should follow proper practices to reduce their risk of exposure to pesticide residues in their diet. Study the impact of other food processing methods, such as cooking or peeling, on pesticide residue levels. Raise public awareness of effective washing techniques. Future research should assess the cumulative risks of pesticide residues in soil, fruits, and the human body. Recommendations: Farmers should strictly adhere to recommended pre-harvest intervals (PHIs) to ensure consumer safety. Regulators should continue to monitor pesticide use and ensure compliance with maximum residue limits (MRLs). Conduct further research to study the environmental fate and cumulative effects of these pesticides under different climatic conditions. Implement integrated pest management (IPM) strategies to reduce reliance on chemical pesticides. Declarations Author contributions: MA: Experimentation, conception and design of the data; prepared all figures; data curation, analysis and interpretation MM: Validation, guided to wrote the main manuscript text, approval of the final version. LE: guided to wrote the main manuscript text, approval of the final version. Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests Funding: None References Al-Mamun, M. et al. (2022). 'Pesticide Residue Monitoring in Fresh Vegetables'. Food Science Reports, 12(2), 15–22. Anastassiades, M. et al. (2003). Journal of AOAC International, 86(2), 412-431. Bempah, C. K., & Donkor, A. (2011). Pesticide residues in fruits at the market level in Accra, Ghana. *Food Control*, 22(3), 313–318. Codex Alimentarius (2022). Maximum Residue Limits for Pesticides in Foods. FAO/WHO. EFSA (2015). Conclusion on the peer review of the pesticide risk assessment of the active substance Lambda-Cyhalothrin. *EFSA Journal*, 13(5), 4095. EPA. (2021). 'Lambda-Cyhalothrin Human Health Risk Assessment'. United States Environmental Protection Agency, p. 90–95. European Committee for Standardization (CEN). (2008). 'Foods of Plant Origin – Determination of Pesticide Residues using GC-MS and/or LC-MS/MS following Acetonitrile Extraction/Partitioning and Clean-up by Dispersive SPE – QuEChERS Method (EN 15662)'. Brussels. FAO (2021). Pesticide Residues in Food. Joint FAO/WHO Meeting, p. 52. Keikotlhaile, B. M., Spanoghe, P., & Steurbaut, W. (2010). Effects of food processing on pesticide residues in fruits and vegetables: A meta-analysis. *Food and Chemical Toxicology*, 48(1), 1–6. Tomlin, C.D.S. (2006). The Pesticide Manual (14th ed.). BCPC. , p. 188 Zhang, W., Jiang, F., & Ou, J. (2011). Global pesticide consumption and pollution: with China as a focus. *Proceedings of the International Academy of Ecology and Environmental Sciences*, 1(2), 125–144. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7272923","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":497987002,"identity":"cc6078cd-4e94-4287-a42a-db6881a86e8e","order_by":0,"name":"Mohammed AbdAlbagi Osman","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYFACHghlwMDYeOADkMHGTqQWCaCWhoMzQFqYidfCwHAYzCakRbe99+Dngop7debshxsO2/zaJs/HzMD44WMObi1mZ84lS884Uyxh2ZPYcDi377ZhGzMDs+TMbXi03MgxkOZtS5AwOADS0nObEaiFjZkXvxbj32At5x82HLbsuW1PjBYziC03gLYw/LidSFjLmTNm1jPOJEjunPGw4WBvw+3kNmbGZvx+Od5jfLugIoHfnD/94YMff27bzm9vPvjhIx4tIICICMY2MNmAXz2KFoY/BBWPglEwCkbBCAQAHAJUxjR5bSgAAAAASUVORK5CYII=","orcid":"","institution":"University Of Sinnar","correspondingAuthor":true,"prefix":"","firstName":"Mohammed","middleName":"AbdAlbagi","lastName":"Osman","suffix":""},{"id":497987004,"identity":"76c67588-6dbe-412f-8858-744c5c30c101","order_by":1,"name":"Mohammed Mobark Awad","email":"","orcid":"","institution":"University of AlButana","correspondingAuthor":false,"prefix":"","firstName":"Mohammed","middleName":"Mobark","lastName":"Awad","suffix":""},{"id":497987006,"identity":"65e97ec5-1c61-4a3e-ab3a-98eda9bc845e","order_by":2,"name":"Lubna ELfatih Khidir","email":"","orcid":"","institution":"Agricultural research corporation","correspondingAuthor":false,"prefix":"","firstName":"Lubna","middleName":"ELfatih","lastName":"Khidir","suffix":""}],"badges":[],"createdAt":"2025-08-01 16:08:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7272923/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7272923/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88816657,"identity":"a31cb392-13a6-45ac-8886-2cc820a4ff3f","added_by":"auto","created_at":"2025-08-11 16:28:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":36112,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7272923/v1/175193c3900fd751bf9f0a2f.png"},{"id":89375781,"identity":"d09af79d-f158-458e-93cf-eb46667853f0","added_by":"auto","created_at":"2025-08-19 11:02:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":396030,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7272923/v1/6d96efeb-cca2-4446-895b-5be5721cdab4.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eThe effect of different household washing methods on removing lambda-cyhalothrin pesticide residues from tomatoes\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFood is the sole means of sustaining life for humans and all living organisms. Food is any substance eaten or drunk to provide nutritional support for the body, or for enjoyment. Given the increasing variety of foods\u0026mdash;fresh, processed, and preserved\u0026mdash;the need for knowledge of various food preservation methods and agricultural pest control methods is growing, starting from the planting stage, then harvesting, through the various stages of manufacturing, and finally the final product.\u003c/p\u003e\u003cp\u003ePesticides are substances that are meant to control pests, including weeds. The term pesticide includes all of the following : herbicide, insecticides (which may include insect growth regulators, termiticides, etc.) nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent animal repellent, antimicrobial, fungicide, disinfectant (antimicrobial), and sanitizer. (Randaall, 2014) The most common of these are herbicides which account for approximately 80% of all pesticide use. Most pesticides are intended to serve as plant protection products (also known as crop protection products). Pesticides can be classified based upon their biological mechanism function or application method. Most pesticides work by poisoning pests. (pesticide applicator, 2018). which in general, protect plants from weeds, fungi, or insects.\u003c/p\u003e\u003cp\u003ePesticides are essential to modern agriculture, but their residues in food raise health and environmental concerns (Akter et al., 2009, p. 34).\u003c/p\u003e\u003cp\u003eLambda-cyhalothrin is a synthetic pyrethroid insecticide widely used in agricultural practices to control a variety of pests, particularly on vegetable and fruit crops such as tomatoes. Its effectiveness in controlling pests, coupled with its relatively low application rates, has made it a popular choice among farmers. It is broadly effective against various insect pests (Tomlin, 2006, p. 188).\u003c/p\u003e\u003cp\u003eHowever, due to its chemical stability and potential health effects, lambda-cyhalothrin residues may remain in food products after harvest, raising concerns about food safety. Exposure to high levels of this pesticide can affect the nervous system, prompting regulatory agencies to establish maximum residue limits (MRLs) for various foodstuffs. Its persistent presence on crops such as tomatoes makes monitoring residue levels crucial to ensuring food safety (FAO, 2021, p. 52).\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eDetailed Analytical Procedures\u003c/p\u003e\n\u003cp\u003e1. Sample Collection and Washing Treatments:\u003c/p\u003e\n\u003cp\u003eFresh tomato samples were randomly collected from Sadat City Market in Egypt, where different samples were collected. The samples were sprayed with lambda-cyhalothrin according to the pesticide spray specifications printed on the pesticide package. The samples were placed under natural conditions to simulate field conditions. The samples were washed approximately 18 hours after the pesticide spray to ensure that the pesticide remained on the surface of the samples and did not degrade rapidly.\u003c/p\u003e\n\u003cp\u003eSample extraction followed the QuEChERS method. The samples were analyzed for lambda-cyhalothrin residues using gas chromatography-mass spectrometry/mass spectrometry techniques.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSample Number and Washing Procedures:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"LTR\"\u003eThe experiment was conducted using 10 independent tomato samples. Each sample was subjected to one of the following washing treatments:\u003c/span\u003e\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"626\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e\u003cspan dir=\"LTR\"\u003eSample code\u003c/span\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 506px;\"\u003etreatment\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e\u003cspan dir=\"LTR\"\u003e1\u003c/span\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;No wash (control group) for 0 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e2\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Tap water for 5 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e3\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Tap water for 10 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e4\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Tap water for 15 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e5\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Saline solution (10% sodium chloride) for 5 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e6\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Saline solution (10% sodium chloride) for 10 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e7\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Saline solution (10% sodium chloride) for 15 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e8\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Water and vinegar solution (1 water : 4 vinegar) for 5 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e9\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Water and vinegar solution (1 water : 4 vinegar) for 10 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e10\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 506px;\"\u003e\u0026nbsp;Water and vinegar solution (1 water : 4 vinegar) for 15 minutes.\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eTomatoes were manually mashed and stirred to simulate common household practices. After washing, samples were homogenized using a stainless steel grinder. Sample extraction and cleanup followed the EN 15662 QuEChERS protocol (CEN, 2008):\u003c/p\u003e\n\u003cp\u003eSamples were processed and analyzed using the QuEChERS extraction method, followed by GC-MS/MS analysis.\u003c/p\u003e\n\u003cp\u003e2. Sample Homogenization\u003c/p\u003e\n\u003cp\u003e- Homogenize the washed samples using a stainless steel blender.\u003c/p\u003e\n\u003cp\u003e- Transfer them to sterile containers.\u003c/p\u003e\n\u003cp\u003e3. Extraction using EN 15662 QuEChERS standard\u003c/p\u003e\n\u003cp\u003eMaterials:\u003c/p\u003e\n\u003cp\u003e\u0026bull; Acetonitrile (HPLC grade)\u003c/p\u003e\n\u003cp\u003e\u0026bull; Magnesium sulfate, sodium chloride, sodium citrate dihydrate, disodium hydrogen citrate\u003c/p\u003e\n\u003cp\u003eMethod:\u003c/p\u003e\n\u003cp\u003e- Weigh 10 grams of homogenized tomatoes into a 50 ml centrifuge tube.\u003c/p\u003e\n\u003cp\u003e- Add 10 ml of acetonitrile and shake for 1 minute.\u003c/p\u003e\n\u003cp\u003e- Add 4 grams of magnesium sulfate, 1 g of sodium chloride, 1 g of sodium citrate dihydrate, and 0.5 g of sodium hydroxide citrate dihydrate.\u003c/p\u003e\n\u003cp\u003e- Shake immediately, then centrifuge at 3500-4000 rpm for 5 minutes.\u003c/p\u003e\n\u003cp\u003e4. Clean-up (d-SPE)\u003c/p\u003e\n\u003cp\u003eMaterials:\u003c/p\u003e\n\u003cp\u003e\u0026bull; 150 mg PSA, 150 mg C18, 900 mg MgSO₄\u003c/p\u003e\n\u003cp\u003eProcedure:\u003c/p\u003e\n\u003cp\u003e- Transfer 6 ml of the supernatant to a 15 ml d-SPE tube. - Stir for 30 seconds, then centrifuge at 12,000 rpm for 5 minutes.\u003c/p\u003e\n\u003cp\u003e5. Filtration and GC-MS/MS Analysis\u003c/p\u003e\n\u003cp\u003e- Extract by filtration using a 0.22 \u0026micro;m PTFE syringe filter into GC-MS/MS vials.\u003c/p\u003e\n\u003cp\u003eGC-MS/MS Parameters:\u003c/p\u003e\n\u003cp\u003e\u0026bull; Column: HP-5ms (30 m \u0026times; 0.25 mm \u0026times; 0.25 \u0026micro;m)\u003c/p\u003e\n\u003cp\u003e\u0026bull; Carrier gas: Helium, 1 mL/min\u003c/p\u003e\n\u003cp\u003e\u0026bull; Injection: Splitless, 1 \u0026micro;L volume, 250\u0026deg;C\u003c/p\u003e\n\u003cp\u003e\u0026bull; Oven: 70\u0026deg;C (1 minute), then increase the temperature to 150\u0026deg;C (25\u0026deg;C/min), then to 280\u0026deg;C (5\u0026deg;C/min), then hold for 5 minutes\u003c/p\u003e\n\u003cp\u003e\u0026bull; Mode: MRM transitions for lambda-cyhalothrin\u003c/p\u003e\n\u003cp\u003e\u0026bull; Tomato samples (3 kg each) were randomly collected from local markets. \u0026bull; Each sample underwent a specific washing process: rinsing with tap water, washing with a 10% saline solution, or washing with a vinegar solution (1:4). Washing times ranged from 5, 10, and 15 minutes, depending on the sample type. Each tomato batch was placed in a plastic container and manually stirred to simulate traditional household cleaning. After treatment, the samples were filtered, and residues were extracted. Analytical measurements were performed using gas chromatography-mass spectrometry (GC-MS/MS) according to standard laboratory pesticide residue protocols. All post-treatment concentrations were recorded for individual analysis.\u003c/p\u003e\n\u003cp\u003eAfter washing, each tomato sample was homogenized using a laboratory grinder. Pesticide residues were extracted using the European method: EN 15662 (QuEChERS). This method involves extracting the analytes with acetonitrile, followed by partitioning with magnesium sulfate and sodium chloride. Clean-up was performed using dispersive solid-phase extraction (d-SPE) with primary secondary amine (PSA) and additional sorbents. The purified extract was filtered and injected into a gas chromatography-mass spectrometry (GC-MS/MS) system to quantify lambda-cyhalothrin residues according to the European guidelines for pesticide residues. The sample was extracted and cleaned up according to the European standard method EN 15662 (QuEChERS) (European Committee for Standardization, (CEN) 2008): a representative sample (10 g) was weighed into a 50 ml centrifuge tube. 10 ml of acetonitrile (MeCN) was added, and the mixture was shaken vigorously for 1 min. A buffer salt mixture containing: 4 g of anhydrous magnesium sulfate (MgSO₄), 1 g of sodium chloride (NaCl), 1 g of trisodium citrate dihydrate (Na₃C₆H₅O₇ 2H₂O), and 0.5 g of disodium hydrogen citrate hemihydrate (Na₂HC₆H₅O₇ 1.5H₂O) was added. The tube was shaken and centrifuged at 3000\u0026ndash;4000 rpm for 5 min. Then, 6 mL of the upper liquid was transferred to a 15 mL d-SPE tube contained 150 mg of PSA, 150 mg of C18, and 900 mg of MgSO₄. After mixing for 30 seconds and centrifuging again, the extract was filtered through a 0.22 \u0026micro;m PTFE filter and analyzed using GC-MS/MS.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe table below show the percentages of remaining concentrations after washing with different detergents.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample code\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eConc/ppb\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePercentage of pesticide removal\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e104.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e00.00%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e92.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e11.45%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e88.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e14.75%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e87.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e15.52%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.16%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e99.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e4.09%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e92.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e10.73%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e103.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.81%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e97.47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6.28%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e94.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9.30%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe figure below show the percentages of remaining concentrations after washing with different detergents.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe results showed the presence of lambda-cyhalothrin residues in tomatoes, even after washing them using different methods, using different materials, and for different periods of time. However, washing with water significantly reduced these residues, removing 11\u0026ndash;15% within 5\u0026ndash;15 minutes. Pesticide removal using a 10% saline solution ranged from 3\u0026ndash;10% within 5\u0026ndash;15 minutes, while pesticide removal using water and vinegar (\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) ranged from 0.8\u0026ndash;9% within 5\u0026ndash;15 minutes.\u003c/p\u003e\u003cp\u003eThe results showed that treating tomatoes sprayed with lambda-cyhalothrin, whether by washing them with tap water, salt water, or vinegar water for different periods of time, removed the pesticide residues.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study confirms the potential for significantly reducing lambda-cyhalothrin residues in tomatoes through appropriate washing techniques, which have been proven effective in experiments. Washing with tap water alone for 15 minutes achieved the highest pesticide removal rate from tomatoes,15.52%.\u003c/p\u003e\u003cp\u003eThe results showed the presence of lambda-cyhalothrin residues in tomatoes, even after washing them with different methods and materials, and for different periods of time. However, washing with water resulted in a significant reduction in these residues, removing 11\u0026ndash;15% within 5\u0026ndash;15 minutes. Pesticide removal using a 10% saline solution ranged from 3\u0026ndash;10% within 5\u0026ndash;15 minutes, while pesticide removal using water and vinegar (1:4) ranged from 0.8-9% within 5\u0026ndash;15 minutes.\u003c/p\u003e\u003cp\u003eThe results showed that treating tomatoes sprayed with lambda-cyhalothrin, whether by washing them with tap water, salt water, or vinegar water for different periods of time, removed a portion of the pesticide residues.\u003c/p\u003e\u003cp\u003edecomposition or cooking.\u003c/p\u003e\u003cp\u003e\u003cb\u003eRecommendations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe study recommends the following:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eConsumers should follow proper practices to reduce their risk of exposure to pesticide residues in their diet.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eStudy the impact of other food processing methods, such as cooking or peeling, on pesticide residue levels.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eRaise public awareness of effective washing techniques.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eFuture research should assess the cumulative risks of pesticide residues in soil, fruits, and the human body. Recommendations:\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eFarmers should strictly adhere to recommended pre-harvest intervals (PHIs) to ensure consumer safety.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eRegulators should continue to monitor pesticide use and ensure compliance with maximum residue limits (MRLs).\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eConduct further research to study the environmental fate and cumulative effects of these pesticides under different climatic conditions.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eImplement integrated pest management (IPM) strategies to reduce reliance on chemical pesticides.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMA: Experimentation, conception and design of the data; prepared all figures; data curation, analysis and interpretation\u003c/p\u003e\n\u003cp\u003eMM: Validation, guided to wrote the main manuscript text, approval of the final version.\u003c/p\u003e\n\u003cp\u003eLE: guided to wrote the main manuscript text, approval of the final version.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests\u003c/p\u003e\n\u003cp\u003eFunding:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAl-Mamun, M. et al. (2022). \u0026apos;Pesticide Residue Monitoring in Fresh Vegetables\u0026apos;. Food Science Reports, 12(2), 15\u0026ndash;22.\u003c/li\u003e\n \u003cli\u003eAnastassiades, M. et al. (2003). Journal of AOAC International, 86(2), 412-431.\u003c/li\u003e\n \u003cli\u003e\u003cspan dir=\"LTR\"\u003eBempah, C. K., \u0026amp; Donkor, A. (2011). Pesticide residues in fruits at the market level in Accra, Ghana. *Food Control*, 22(3), 313\u0026ndash;318.\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eCodex Alimentarius (2022). Maximum Residue Limits for Pesticides in Foods. FAO/WHO.\u003c/li\u003e\n \u003cli\u003e\u003cspan dir=\"LTR\"\u003eEFSA (2015). Conclusion on the peer review of the pesticide risk assessment of the active substance Lambda-Cyhalothrin. *EFSA Journal*, 13(5), 4095.\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eEPA. (2021). \u0026apos;Lambda-Cyhalothrin Human Health Risk Assessment\u0026apos;. United States Environmental Protection Agency, p. 90\u0026ndash;95.\u003c/li\u003e\n \u003cli\u003eEuropean Committee for Standardization (CEN). (2008). \u0026apos;Foods of Plant Origin \u0026ndash; Determination of Pesticide Residues using GC-MS and/or LC-MS/MS following Acetonitrile Extraction/Partitioning and Clean-up by Dispersive SPE \u0026ndash; QuEChERS Method (EN 15662)\u0026apos;. Brussels.\u003c/li\u003e\n \u003cli\u003eFAO (2021). Pesticide Residues in Food. Joint FAO/WHO Meeting, p. 52.\u003c/li\u003e\n \u003cli\u003e\u003cspan dir=\"LTR\"\u003eKeikotlhaile, B. M., Spanoghe, P., \u0026amp; Steurbaut, W. (2010). Effects of food processing on pesticide residues in fruits and vegetables: A meta-analysis. *Food and Chemical Toxicology*, 48(1), 1\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eTomlin, C.D.S. (2006). The Pesticide Manual (14th ed.). BCPC. , p. 188\u003c/li\u003e\n \u003cli\u003e\u003cspan dir=\"LTR\"\u003eZhang, W., Jiang, F., \u0026amp; Ou, J. (2011). Global pesticide consumption and pollution: with China as a focus. *Proceedings of the International Academy of Ecology and Environmental Sciences*, 1(2), 125\u0026ndash;144.\u003c/span\u003e\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Pesticides, Pesticide residues, Lambda-cyhalothrin, Tomatoes, Household washing","lastPublishedDoi":"10.21203/rs.3.rs-7272923/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7272923/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigated the presence of residues of the pesticide lambda-cyhalothrin and its behavior with different washing treatments in tomato samples using gas chromatography-tandem mass spectrometry (GC-MS/MS) technique. Ten tomato samples were subjected to different household washing treatments (tap water, 10% sodium chloride solution, 20% vinegar-water solution (1:4), followed by extraction and analysis of the pesticide using the QuEChERS technique. Residue levels varied by treatment, with the unwashed sample having a concentration of 104.00ppb, with a 00.0% removal rate. The samples were as follows: (92.09, 88.66, 87.85, 100.71, 99.75, 92.84, 103.16, 97.47, 94.33)ppb and (11.45, 14.75, 15.52, 3.16, 4.09, 10.73, 0.81, 6.28, 930)% respectively. Washing with tap water only for 15 minutes achieved the highest removal rate of tomatoes, with a percentage of (15.52%) while washing with20% vinegar-water solution (1:4), for 5 minutes recorded the lowest removal rate, with a percentage of (0.81%). This study confirms that lambda-cyhalothrin residues in tomatoes can be significantly reduced through appropriate washing techniques. The study recommended that consumers follow these practices to reduce the risk of dietary exposure to pesticide residues. It also recommended that the effect of other food processing methods, such as cooking or peeling, on pesticide residue levels be studied. Public awareness should also be raised about effective washing techniques. Future research should assess the cumulative risks of pesticide residues in In the soil, in the fruit, and in the human body.\u003c/p\u003e","manuscriptTitle":"The effect of different household washing methods on removing lambda-cyhalothrin pesticide residues from tomatoes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-11 16:28:51","doi":"10.21203/rs.3.rs-7272923/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0c364baf-1aa9-4f32-8ad3-cc92598fcf88","owner":[],"postedDate":"August 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-19T10:53:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-11 16:28:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7272923","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7272923","identity":"rs-7272923","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}