Washing Pesticides Off Produce: What the Baking Soda Study Found and What Actually Works

A widely shared study from the University of Massachusetts tested three ways of cleaning pesticide residues from apples: tap water, a bleach solution used commercially, and a homemade baking soda solution. The winner, baking soda, made headlines and is now a staple of kitchen advice. Many people also buy commercial produce washes or use vinegar. But how much do these methods remove, and does washing matter for health?

This article reviews what the research shows about removing pesticide residues and germs from produce, explains the difference between surface and absorbed residues, compares washing methods, and puts residues in context with the benefits of eating fruits and vegetables.

Does washing produce remove pesticides? It removes some, but not all. A 2017 study found that soaking apples in a baking soda solution for 12 to 15 minutes removed surface residues of two pesticides better than water or bleach, yet residues that had soaked into the fruit could not be washed off. Plain running water, the FDA’s advice, removes dirt, germs, and loose residues. The bigger message: eat produce anyway, because the benefits outweigh residue risks.

What Did the Baking Soda Pesticide Study Find?

The study found baking soda soaks removed surface residues of two pesticides more completely than water or a bleach wash, but could not remove residues that had penetrated into the fruit. The 2017 study, published in the Journal of Agricultural and Food Chemistry by Tianxi Yang, Lili He, and colleagues at the University of Massachusetts Amherst, applied two pesticides to organic Gala apples: thiabendazole, a systemic fungicide that can move into plant tissue, and phosmet, a non-systemic insecticide that mainly stays on the surface. After 24 hours, apples were washed with tap water, a bleach solution of the type approved for postharvest produce washing, or a 1 percent sodium bicarbonate (baking soda) solution. Using surface-enhanced Raman spectroscopy and mass spectrometry, the researchers found that baking soda was most effective, completely removing surface residues of thiabendazole after 12 minutes and phosmet after 15 minutes. However, about 20 percent of the applied thiabendazole and 4.4 percent of phosmet had penetrated into the apples, and these internal residues could not be washed off. Thiabendazole penetrated about four times deeper into the peel than phosmet.

The study had important limits: it used only two pesticides on one fruit, applied at controlled concentrations to apples that had no prior residues, and measured residues after only 24 hours, whereas commercial produce may have been treated days or weeks before purchase. Still, it showed that baking soda can enhance removal of some surface residues and that washing alone cannot remove absorbed pesticides.

Which Way of Washing Produce Works Best?

For surface residues, a baking soda soak worked best in the lab, followed by plain water with rubbing; vinegar and salt help modestly, and commercial washes are no better than water. A 2014 review in the Journal of Food Science and Technology by U. Bajwa and K. S. Sandhu summarized research on how food handling and processing affect pesticide residues. Washing with water or soaking in solutions of salt and other agents was reported to reduce residues, preparatory steps like peeling and trimming further reduced them, and thermal processing such as blanching, boiling, and cooking reduced many residues, though results varied by pesticide. Residues that are systemic or fat-soluble are generally harder to remove than water-soluble surface residues.

How Does the FDA Say to Wash Produce?

The FDA advises washing produce under plain running water while rubbing it, scrubbing firm items with a brush, and skipping soap and commercial produce washes. The FDA’s consumer guidance on cleaning fruits and vegetables focuses primarily on reducing germs that cause foodborne illness. It advises washing hands for 20 seconds before and after handling produce, choosing produce that is not bruised or damaged, rinsing produce before peeling so dirt and bacteria are not transferred by the knife, gently rubbing produce under plain running water, scrubbing firm produce such as melons and cucumbers with a clean brush, drying produce with a clean cloth or paper towel, and removing the outermost leaves of lettuce or cabbage. The FDA states there is no need to use soap or a produce wash. Produce labeled prewashed or ready-to-eat does not need rewashing.

Are Pesticide Residues on Produce Dangerous?

For most people, no. Residues on U.S. produce are typically well below safety limits, and the health benefits of eating fruits and vegetables far outweigh any risk from residues. The USDA’s Pesticide Data Program tests thousands of samples of fruits, vegetables, and other foods each year, after washing and peeling as consumers typically would, and has consistently reported that the vast majority of samples have residues below EPA tolerances, with a portion having no detectable residues. Some produce, such as strawberries, spinach, and apples, more often carries multiple residues. A 2012 systematic review in the Annals of Internal Medicine by Crystal Smith-Spangler and colleagues found that organic produce had a lower risk of detectable pesticide residues than conventional produce, though residues in both usually fell within safety limits.

Nutrition experts emphasize that the health benefits of eating fruits and vegetables, including lower risks of heart disease, stroke, and some cancers, far outweigh potential risks from typical residue levels. Concern about pesticides should not discourage people from eating produce. Instead, practical steps such as washing, choosing organic versions of foods that tend to carry higher residues when affordable, and eating a variety of foods can reduce exposure while preserving benefits.

Who Should Be Most Careful About Pesticide Residues?

Pregnant women, infants, and young children are most sensitive, so extra washing, peeling some items, and choosing organic for the highest-residue produce are reasonable precautions for them. Pregnant people and young children may wish to take extra steps to reduce pesticide exposure, given research on developmental sensitivity to certain pesticides, such as organophosphates. Farmworker families and people living near treated fields have higher exposures from other sources, making dietary steps a smaller part of their total exposure. For everyone, washing produce primarily protects against foodborne germs, which cause millions of illnesses each year, so the habit is worthwhile regardless of pesticide concerns.

Why Can’t Washing Remove All Pesticides?

Washing removes only what sits on the surface. Pesticides fall into two broad types. Contact or non-systemic pesticides, like the insecticide phosmet, stay mostly on the outside of produce, so washing and peeling remove much of them. Systemic pesticides, like the fungicide thiabendazole, are absorbed into the plant and move through its tissues, so they end up beneath the skin where no amount of washing can reach. In the 2017 study, about 20 percent of the applied thiabendazole had moved into the apples within 24 hours, roughly four times deeper than phosmet. This is why residue levels, not just washing, depend on which pesticides were used and how.

Does Peeling Remove More Pesticide Than Washing?

Peeling removes more residue than washing because it takes off the skin where many residues concentrate, including some that have penetrated slightly below the surface. A 2010 meta-analysis in Food and Chemical Toxicology by Keikotlhaile and colleagues found that food processing steps such as washing, peeling, and cooking generally reduced pesticide residues, with peeling among the most effective. The trade-off is that the peel of many fruits and vegetables also holds much of their fiber, vitamins, and beneficial plant compounds. For most people the nutritional loss from always peeling is not worth it; peeling makes more sense for produce likely to carry higher residues or for sensitive groups.

Does Cooking Reduce Pesticide Residues?

Cooking can lower residues of some pesticides through heat breakdown, evaporation, and the discarding of cooking water, though it concentrates others when food loses water. The same 2010 meta-analysis found that processing usually reduced residues overall, but effects varied by pesticide and method. Boiling and discarding the water removes more water-soluble residues than steaming or microwaving. Cooking is not a reliable way to remove pesticides on its own, but combined with washing it further reduces exposure.

What About the “Dirty Dozen” and “Clean Fifteen”?

Each year, an advocacy group ranks produce by pesticide residues, labeling the highest as the “Dirty Dozen” (often strawberries, spinach, and leafy greens) and the lowest as the “Clean Fifteen” (such as avocados, sweet corn, and onions). These lists can help prioritize which items to buy organic, but scientists caution that they rank by number of residues detected rather than by actual risk, and that residues on conventional produce are generally within safety limits. The lists should not discourage anyone from eating fruits and vegetables; if organic is unaffordable, conventional produce is far better than skipping produce.

Does Buying Organic Reduce Pesticide Exposure?

Yes. Organic farming prohibits synthetic pesticides, so organic produce carries fewer and lower synthetic residues. A 2019 study in Environmental Research by Carly Hyland and colleagues found that when families switched to an all-organic diet for six days, urinary levels of several pesticides and their breakdown products dropped substantially, including a large fall in a metabolite of the insecticide chlorpyrifos. Organic produce can still carry trace residues from soil, water, or drift, and organic farming uses some natural pesticides, but overall synthetic residue exposure is lower. For people who cannot buy all organic, focusing on the highest-residue items offers the most benefit.

Practical Steps to Reduce Residues

Rinse all produce under running water and rub or scrub it just before eating, even items with inedible peels like melons, since cutting can drag surface contamination inside. Soaking in a baking soda solution (about a teaspoon per two cups of water) for 12 to 15 minutes, then rinsing, can help with some surface residues when you have time. Peel produce likely to carry higher residues when convenient, discard the outer leaves of leafy vegetables, eat a varied diet so you are not exposed to the same residues repeatedly, and choose organic for the items that matter most to you. Above all, keep eating plenty of fruits and vegetables.

Washing Produce to Remove Germs, Not Just Pesticides

For day-to-day safety, washing matters more for germs than for pesticides. Fresh produce can carry bacteria such as Salmonella, E. coli, and Listeria from soil, water, animals, or handling, and leafy greens and sprouts have caused major outbreaks. Rinsing under running water and rubbing removes much of this surface contamination and dirt. Washing cannot sterilize produce or remove bacteria that have gotten inside, which is why safe handling, refrigeration, and cooking when appropriate also matter. Wash produce just before eating rather than before storing, since moisture can encourage spoilage.

Common Washing Mistakes to Avoid

Several habits reduce the benefit of washing or add risk. Using soap, detergent, or bleach on produce is discouraged by the FDA because these are not meant to be eaten and can leave their own residues. Washing produce long before use can speed spoilage. Skipping items with inedible rinds, such as melons, avocados, and citrus, is a mistake because knives can carry surface germs and residues into the flesh. Re-using dirty cloths or sponges can spread bacteria. The simplest reliable approach is plain running water, clean hands, and clean surfaces, with a longer baking soda soak when you want extra residue removal.

Frequently Asked Questions

What is the best way to wash pesticides off produce?

Rubbing produce under plain running water removes dirt, germs, and many loosely bound surface residues, and it is what the FDA recommends. A 2017 lab study found that soaking apples in a baking soda solution for 12 to 15 minutes removed surface residues of two pesticides more completely, but no washing method can remove residues that have soaked into the fruit.

How do I make a baking soda wash for fruits and vegetables?

Use about a 1 percent solution, roughly one teaspoon of baking soda dissolved in two cups of water. Soak the produce for 12 to 15 minutes, then rinse it thoroughly under running water before eating. This works best for firm produce with surface residues and is impractical for delicate items like berries, which are better rinsed quickly.

Should I use soap or a commercial produce wash?

No. The FDA advises against washing produce with soap, detergent, or commercial produce washes. Soaps are not intended to be eaten and can leave their own residues, and studies show commercial washes are generally no more effective than plain water. Running water with rubbing, or a baking soda soak for extra residue removal, is all that is needed.

Does peeling remove pesticides better than washing?

Peeling removes more residue than washing because it takes off the skin, where many residues concentrate, including some that have penetrated just below the surface. The downside is that peels often hold much of a fruit or vegetable’s fiber and nutrients, so routine peeling is not usually worth it except for higher-residue items or for sensitive groups like young children.

Is organic produce free of pesticides?

Not entirely, but it carries far fewer synthetic pesticide residues. Organic farming prohibits synthetic pesticides, and studies show switching to an organic diet quickly lowers urinary pesticide levels. Organic produce can still contain trace residues from drift, soil, or approved natural pesticides, so it is lower in synthetic residues rather than completely residue-free.

Should I stop eating conventional produce because of pesticides?

No. Residues on conventional U.S. produce are generally within safety limits, and the health benefits of eating fruits and vegetables strongly outweigh the small risks from residues. Washing, occasional peeling, variety, and choosing organic for the highest-residue items all help, but eating plenty of produce, organic or not, is far better than cutting back.

References

1. Yang T, Doherty J, Zhao B, et al. Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples. Journal of Agricultural and Food Chemistry. 2017;65(44):9744–9752. PMID 29067814
2. Bajwa U, Sandhu KS. Effect of handling and processing on pesticide residues in food – a review. Journal of Food Science and Technology. 2014;51(2):201–220. PMID 24493878
3. Smith-Spangler C, Brandeau ML, Hunter GE, et al. Are organic foods safer or healthier than conventional alternatives? A systematic review. Annals of Internal Medicine. 2012;157(5):348–366. PMID 22944875
4. U.S. Food and Drug Administration. 7 Tips for Cleaning Fruits, Vegetables. fda.gov
5. USDA Agricultural Marketing Service. Pesticide Data Program. ams.usda.gov

Last updated: October 6, 2026