Which fruits and vegetables carry the most pesticide residues, and does washing help?

What national testing shows. USDA's Pesticide Data Program buys produce near the point of sale, rinses it for 15 to 20 seconds under cold running water as a shopper might, then tests it. In 2024, more than 99% of samples were under EPA limits (tolerances), 42.3% had no detectable residue, and 0.77% were over the limit, mostly imports³. Detection varies by crop. Share of samples with no detectable residue:

• Usually clean: sweet corn 90%, pineapple 89%, avocado 88%, onions 72%.
• In between: head lettuce 47%, tomatillos 22%, cherry tomatoes 21%.
• Usually carry residues: blackberries 18%, cucumbers 16%, leaf lettuce 11%, oranges 6%, apples 6%, potatoes 2%.

USDA rotates crops, so strawberries, spinach, kale, grapes and peaches were not tested in 2024; advocacy lists have long flagged them⁹.

Detected is not the same as dangerous. An analysis of the twelve items on one advocacy group's list found every exposure estimate well below chronic reference doses, concluded the risk was negligible, and said the group's ranking did not quantify how much consumers actually eat⁹.

Observational studies are less reassuring. In women having fertility treatment, those eating the most high-residue produce had lower pregnancy and live-birth rates⁵, and a 2025 study found lower fertilization rates when the male partner ate more⁶. In three cohorts, low-residue produce went with lower mortality, but high-residue produce showed no clear benefit⁴. These use a crude score (people in its top fifth had only 13% higher urinary metabolites¹⁰), and cannot prove cause.

Does organic help? On exposure, yes. Thirteen adults eating at least 80% organic food for a week had 89% lower urinary organophosphate metabolites⁷. In 23 children, malathion and chlorpyrifos markers fell to undetectable levels within days⁸. Thirteen pesticide markers fell in four families on an organic diet¹¹. Whether health improves is unproven.

Washing. Tap-water rinsing removed nine of twelve pesticides tested, but not vinclozolin, bifenthrin or chlorpyrifos². A 1% baking soda solution cleared surface residues from apples in 12 to 15 minutes, better than water or bleach, but residue that had soaked in stayed¹.

Cost and priorities. Organic produce usually costs more, so be selective: organic for what you eat most of and what tests highest, conventional for the rest.

National testing data

The 2024 USDA summary covered 9,872 samples (9,165 fruit and vegetable, 531 almond, 176 salmon). Samples were chosen without regard to origin or organic label. Residues exceeded the tolerance in 76 samples (0.77%), 63 of them imports, and 361 samples (3.7%) had residues with no established tolerance. In 39.8% of samples more than one pesticide was found. Roughly three-quarters of apples carried three or more, while avocados (88.1% none), pineapple (88.7%), fresh sweet corn (90.0%) and frozen sweet corn (97.0%) were mostly clean; 98% of potatoes carried at least one, typically one pesticide³.

Risk assessment versus epidemiology

The 2011 toxicology analysis used USDA data to estimate exposure to the ten most-detected residues on each of twelve commodities on an advocacy list: all 120 estimates were far below reference doses, one exceeded 1% (methamidophos on bell peppers, 2%), and three-quarters were below 0.01%. The authors concluded that organic substitution would not appreciably reduce risk⁹. A limit of this approach is that reference doses are set chemical by chemical, while real diets contain mixtures.

Epidemiology is less reassuring. In the EARTH study, 325 women had 541 fertility-treatment cycles. Women in the top quarter of high-residue produce intake (2.3 or more servings a day) had an 18% lower probability of clinical pregnancy (95% CI 5% to 30%) and a 26% lower probability of live birth (13% to 37%) than those in the bottom quarter (under 1 serving), while low-residue produce was unrelated⁵. In 244 men and 437 cycles, adjusted fertilization rates were 0.78 in the lowest and 0.69 in the highest quartile of high-residue intake (P for trend 0.04), and the authors note the implications for natural fertility are unclear⁶. In the Nurses' Health Studies and Health Professionals Follow-up Study (160,880 people, 27,026 deaths), four or more servings a day of low-residue produce went with 36% lower mortality (95% CI 32% to 41%), whereas high-residue produce gave a hazard ratio of 0.93 (0.81 to 1.07); the authors suggest residues may offset produce's benefit⁴. All three come from one research group and rely on residue scores derived from national data rather than measured residues. When validated against urinary metabolites in 3,679 NHANES participants, the top fifth of the score had metabolite levels 13.0% higher (8.3% to 17.7%) than the bottom fifth, which shows the score ranks exposure only roughly¹⁰.

Organic-diet trials

In a randomized crossover trial, 13 adults ate a diet of at least 80% organic or conventional food for seven days each. Total dialkylphosphate metabolites were 89% lower after the organic week and dimethyl metabolites 96% lower; diethyl metabolites halved but not significantly⁷. In 23 school-age children, five days of mostly organic food brought malathion and chlorpyrifos metabolites to undetectable levels, and they stayed there until conventional food returned; the authors judged diet to be their main exposure route⁸. In four US families (16 people, 158 urine samples), 13 metabolites or parent compounds fell, including clothianidin by 82.7%, a malathion metabolite by 95.0% and a chlorpyrifos metabolite by 60.7%¹¹. These trials measure exposure, not disease, and the last had four families.

Washing

Rinsing was tested on field-treated crops: nine of twelve pesticides were reduced, three (vinclozolin, bifenthrin, chlorpyrifos) were not, and rinsability did not follow water solubility². On apples, 10 mg/mL sodium bicarbonate removed surface thiabendazole in 12 minutes and phosmet in 15 minutes, outperforming tap water and bleach. But 20% of the thiabendazole and 4.4% of the phosmet had already penetrated the fruit and were not removed, and peeling removes them along with beneficial peel compounds¹.

Where the evidence conflicts

Toxicology-based estimates say typical dietary exposure is negligible; some cohorts suggest otherwise. Detection frequency is not dose. USDA tests a mix of organic and conventional produce and rotates crops yearly. We found no trial of health outcomes for organic versus conventional produce.

Bottom line

Confidence is 3 of 5. Residue differences by crop, the benefit of washing and peeling, and the drop in urinary markers on organic diets are well documented. Whether typical residues harm health remains uncertain, which is why a selective, budget-aware approach is sensible.