Editor’s Note: This article has been updated to reflect the 2022 EWG Dirty Dozen and Clean Fifteen lists.
The agricultural industry is addicted to pesticides, and the entire world is paying the price. The US Environmental Protection Agency (EPA) reports that global pesticide use in 2012 amounted to approximately six billion pounds. Unfortunately, they haven’t published a report since then, but the number likely hasn’t improved and may have gotten worse.
While the term “pesticide” implies that these chemicals target and kill “pests,” a better name would be “biocides” — destroyers of life, because they do a lot more than poison pests.
How common is it for US produce to be contaminated? “More than 70% of nonorganic fresh produce sold in the U.S. contains residues of potentially harmful pesticides,” according to the Environmental Working Group (EWG). And while we could go into detail about all the types and dangers of pesticides, we’ve already written an in-depth article about them, which you can read here.
Don’t Let Pesticides Stop You from Eating Fruits & Vegetables
In this article, we’re going to review the most and least pesticide-contaminated produce, so you can make wise buying decisions.
One thing to remember — thousands of studies, published in peer-reviewed journals, tell us clearly that eating more fruits and vegetables can be good for your health. The more of these foods you eat, the longer you’re likely to live, and the less likely you are to develop most of the major chronic illnesses of our times.
Of course, in these studies, most of the fruits and vegetables were grown commercially, and many were contaminated with pesticides. So as you read about pesticide contamination of fruits and vegetables, please use this guidance as it is intended — to help you to know which foods are most important to buy organic, if possible. If you can’t afford or can’t access organic produce, don’t let that stop you from eating fruits and veggies. Remember, if you’re choosing between an organic donut and nonorganic kale… go for the kale. Just please wash it well (here’s our article on how to wash pesticides off produce, if you’d like some guidance.)
Who Tests for Pesticide Residue?
For this article, I’m relying on two nongovernmental organizations for the data on which fruits and vegetables are the dirtiest and cleanest. The best known of these groups is EWG, which has published its Shopper’s Guide to Pesticides in Produce annually since 2004. Their produce guide identifies the least and most pesticide-contaminated produce — also known as their Clean Fifteen and Dirty Dozen — based on thousands of tests conducted by both the USDA and the FDA. In carrying out these tests, the produce is made “plate-ready” — washed, peeled, and ready to eat — before being analyzed. So the residues found in these studies are likely to be the same as those you’re exposed to when you eat conventionally grown fruits and veggies.
In 2020, Consumer Reports (CR) released their own report based on USDA data. CR came up with their own ratings (which not surprisingly look a lot like the ones they bestow on clothes dryers and new cars), by running the USDA numbers through several filters. These include the total number of pesticides; the level of pesticides on fruits and vegetables; the frequency with which they were detected; and their toxicity. CR factors in the pesticide’s Food Quality Safety Factor (FQPA), which is published by the Environmental Protection Agency (EPA) to avoid underestimating potential harms. The CR findings overlap significantly with those of EWG. But unlike EWG, CR makes distinctions between US-grown and imported foods, as well as conventional and organic.
Below, I summarize EWG’s Dirty Dozen and Clean Fifteen. Bear in mind as you go through the list that they are looking exclusively at conventionally grown produce, not organic. And, of course, your best choice will almost always be homegrown food, since you can control the methods you use to nourish and protect your crops. (Read our article on how to start growing an edible garden.)
If you can’t grow any or all of your own produce, this shopper’s guide can help you make wise consumer choices. Use it when you shop for fresh produce, either at the grocery store or your local farmers market, to determine which foods to buy organic.
One more thing before we dive in — this guide looks at pesticide residues only at the consumer level. In some cases, the ratings might be very different if the researchers factored in the exposure of farmworkers and communities where the crops are grown. For example, conventional imported bananas are rated “very good” by CR (because the peel provides pesticide protection for the fruit). But public health research shows that farmworkers exposed to the pesticides used on conventional bananas develop up to 80% more genetic anomalies (i.e., potentially cancer-causing mutations) than those who work in organic or “ecological” farms that do not use conventional pesticides.
I am not aware of any convenient database or app to help you prioritize food choices to protect farmworkers. If this is important to you (and it certainly is to me), my recommendation is to choose organic when you can.
The Dirty Dozen: The Most Pesticide-Contaminated Produce
This list comes from EWG’s Dirty Dozen list. These fruits and vegetables are the foods with the most pesticide residues and are therefore the ones that are most important to buy organic if you can.
If you want to avoid exposure to multiple noxious chemicals, including dangerous fumigants that build up in the plant tissue, the fruit, and the soil, the most important food to only buy organic is the strawberry. Most of the fresh strawberries sold in the US come from California. Data from 2015 revealed that, per acre, strawberries receive 60 times more pesticide application by weight than corn, which itself is a pesticide-intensive crop. In fact, a jaw-dropping 99% of nonorganic strawberry samples had detectable pesticide residue.
But it wasn’t just the amount — the variety and toxicity of the chemicals were also problematic. While most crops showed residues of just over 2 pesticides per sample, strawberries averaged almost 8 — with 30% at 10 or more. And some of these pesticides, according to EWG, “have been linked to cancer and reproductive damage, or… are banned in Europe.”
If you like strawberries (and a lot of us do!), you have a few options. You can grow them yourself. (It’s not that hard, and you don’t need a lot of land. Even a container on a sunny porch should do the trick). Or, buy fresh or frozen strawberries, and choose organic.
If strawberries win the dubious distinction of the highest amount of pesticides, spinach holds the distinction of highest pesticide residues by weight. The biggest culprit in testing was permethrin, a neurotoxin insecticide banned in Europe linked to ADHD and various neurological impairments in children.
And speaking of bans, let’s talk about DDT for a minute. The pesticide that was banned in the US in 1972 after being indicted for multiple harms in Rachel Carson’s book Silent Spring can still shockingly be found on 40% of spinach sampled by the USDA in 2016. DDT, like many other pesticides, has a nasty ability to persist in the environment — even after almost half a century.
Your best bet, aside from growing your own spinach, is buying organic spinach, according to CR. Next best is imported frozen spinach, as that’s been found to be lower in pesticides than spinach grown in the US. In any case, always wash spinach well, as pesticide levels were found to be higher in unwashed spinach than in the washed spinach tested by the USDA.
3. Kale, Collards, & Mustard Greens
Given leafy greens’ (like kale) well-justified popularity as nutritional powerhouses, I’m sad to report that they’re among some of the most contaminated crops in the US. In 2017, the USDA found that almost 60% of nonorganic kale samples were contaminated with the herbicide DCPA (marketed as Dacthal), which has been banned in Europe since 2009 because of cancer risks. And in 2019, 35% of examined samples of collard and mustard greens were also contaminated with Dacthal. DCPA’s main application is to kill crabgrass, which can outcompete edible leafy greens in poor soil conditions. Rather than remedy the soil, farmers are told to keep pouring on the chemicals.
The problem here is that DCPA was identified as a possible human carcinogen by the EPA as early as 1995. The data was so alarming, the manufacturer actually petitioned the EPA in 2005 to terminate its use on a variety of crops. Unfortunately, the ag industry has ignored the science and continues to douse our leafy greens in it. In the US, the only kale, collards, and mustard greens deemed generally free from DCPA are those grown organically.
Named after the divine drink of the Olympian gods, it’s a cruel irony that these delicious fruits are often fouled by pesticide residues. The USDA found 33 pesticide residues in nectarine samples, including 5 known or probable carcinogens, 17 suspected hormone disruptors, and 6 developmental or reproductive toxins. Oh, and if that’s not bad enough, they were also found to contain 10 chemicals toxic to honeybees, our most important and most endangered pollinators.
The good news is, organic nectarines are low in pesticides, according to CR’s data.
At first blush, apples look pretty good. They’re treated with fewer pesticides than many other crops, averaging 4.4 pesticide residues per sample. And they aren’t heavily treated while growing. The problem occurs after harvest when conventional apples are bathed in a chemical named diphenylamine, which keeps the skins pretty while the apples are in cold storage. American regulators decided that diphenylamine didn’t pose any unacceptable risks — in contrast to European officials, who were swayed by evidence that by-products of diphenylamine may contribute to cancers of the stomach and esophagus. For this reason, American-grown conventional apples are banned in Europe.
Some apples have been bioengineered, also for cosmetic rather than functional reasons. Arctic apples, for example, are spliced with genes that prevent the flesh from browning when cut open. (To avoid this dreaded condition, you can either eat them once cut, soak them in diluted lemon juice, or just be OK with apples that turn brown when their cut skin is exposed to the air.) Since BEs (GMOs) are viewed by some as a giant uncontrolled experiment in overriding the laws of nature — and there’s plenty of reason to be skeptical about industry claims of safety — there are reasons you may want to avoid these “Franken-apples.”
Your best bets when it comes to apples are homegrown (a well-tended apple tree can last up to five generations) or organic and non-GMO varieties.
EWG tells us that nonorganic grapes are loaded with pesticide residues, including 8 cancer-causers, 17 suspected hormone disruptors, 10 neurotoxins, and 4 developmental or reproductive toxins. Plus, they’re often treated with 19 pesticides that are toxic to honeybees.
The only good thing you can say about nonorganic grapes is that they’re better than nonorganic raisins. According to EWG, almost 100% of samples of nonorganic raisins contained residues from two or more pesticides.
In a discrepancy that I can’t quite resolve, CR rates domestic, nonorganic grapes as very good, and imported ones as good. I hope they’ll publish the data behind their findings, as well as details of their methodology, so the public will be able to make grape decisions with more confidence. To be safe, my recommendation is to buy organic grapes and raisins.
Sadly, wines — and vinegars like red wine or balsamic — are also subject to potentially harmful doses of pesticides. Roundup is commonly used in nonorganic vineyards, at more than a pound and a half per acre, as are various other fumigants, herbicides, and nematicides (killers of microscopic critters called nematodes, the problematic varieties of which flourish in poor soil). Pesticide residues found in wine rival those found in raw grapes, indicating that the winemaking process isn’t protective. These are good reasons to opt for wines made from organically grown grapes, if you choose to drink wine at all. (Read about the health effects of wine and other forms of alcohol here.)
7. Bell and Hot Peppers
Overall, peppers had the most types of pesticides detected — a whopping 115 in total. Two pesticides in particular showed up more often than not among tested bell and hot pepper samples. Acephate and chlorpyrifos are organophosphate insecticides that attack the acetylcholinesterase enzyme in insects and mammals. This enzyme helps convert the neurotransmitter acetylcholine into acetic acid and choline compounds in the body.
Insecticides like acephate and chlorpyrifos are especially harmful to children’s developing brains and can cause nervous system problems and other unpleasant side effects among humans. Although they’re banned in the EU, the US has not taken steps towards an outright ban on these toxic chemicals, which sadly still end up in our food supply.
To avoid potential exposure to any of 115 pesticides, bell and hot peppers are foods you’ll want to purchase organic as much as possible — or grow your own.
Almost half of the cherries sampled by the USDA contained residues of bifenthrin, a neurotoxin that kills insects by paralysis. It’s moderately harmful to mammals (including humans) and can wreak havoc on fish and their marine ecosystems. It also appears to cause cancer in mice but not rats, so we really don’t know what that says about carcinogenesis in humans. (Our view on the use of animals in medical research is here.) But add to this nasty chemical the residues of 42 others found on cherries by USDA testing, and you have a recipe for individual and environmental concern.
Aside from homegrown (there are many varieties of cherry trees and bushes that produce delicious fruit you’ll never find in a supermarket), your best bet here is frozen, domestic, organic cherries. Even imported organic cherries were rated only “fair” by CR, based on suspicions of inadequate oversight of organic standards by countries such as Turkey and China. Fresh organic cherries could be a solid choice, too, if you have access to them.
EWG and CR agree that fresh, nonorganic peaches are among the foods with the most pesticides in the US. Samples examined by the USDA found residues of 62 separate pesticides, including a whopping 24 suspected hormone disruptors and a dozen neurotoxins on peaches.
If possible, stick to organic peaches. CR also reported that nonorganic, canned peaches are low in pesticides and received an “excellent” rating. While we don’t typically recommend canned fruit, if you do choose to buy canned peaches, look for some that are packed in organic fruit juice instead of syrup.
Four out of 10 samples of nonorganic pears were found to have residue of pyrimethanil, a fungicide shown to cause underdevelopment of ovaries and interference in normal sexual differentiation in tree frogs. In other animal tests, pyrimethanil caused damage to livers, kidneys, and thyroid glands. The USDA classifies it as a Group C (potential) carcinogen.
A quarter of pear samples were also contaminated with o-Phenylphenol, a mold growth retardant whose jocular rhyming name belies its nasty effects: it’s a known carcinogen, suspected hormone disruptor, and developmental toxin.
When buying fresh pears, choose organic if possible. Both domestic and imported pear samples were rated “excellent” by CR.
Celery doesn’t come with the worst pesticides out there but still contains quite a few of them. According to the USDA, 100% of celery samples had residues of chlorantraniliprole, which appears to have mild effects on humans but can be lethal to honeybees. Samples also contained spinosad, which kills mosquito larvae and harms bees.
Your best celery options include growing your own or purchasing domestic or imported organic celery.
The good news about tomatoes is that, even though they contain many different kinds of pesticide residues (69 in cherry tomatoes, and 35 in regular varieties), the chance of you finding a tomato with a specific pesticide is smaller than the crops mentioned so far. The most common pesticide found in cherry tomatoes, bifenthrin, was in under one-quarter of samples. And the most frequently found pesticide in regular tomatoes, endosulfan II (which sounds like a bad video game sequel), was present in just 17% of tested samples.
Even so, EWG advises you to choose organic tomatoes when you can. Both fresh and canned organic tomatoes appear to be fine. And good news for all aspiring home gardeners — tomatoes are one of the easiest crops to grow. A single cherry tomato plant grown in a container on a patio can provide you and your family with a season’s worth of salad additions. With hundreds of hybrids and heirloom varieties, you’re likely to find tomatoes that fit your gardening space and your taste buds.
The Clean Fifteen: The Least Pesticide-Contaminated Produce
Now that you’ve made it through the scary part of this article, it’s time to reward yourself by discovering the 15 least pesticide-contaminated crops.
Whew! Avocados topped the Clean Fifteen list as one of the most pesticide-free, conventionally grown produce items tested. Fewer than 2% of avocado samples showed any detectable pesticide residue. And the single pesticide found on avocados, imiprothrin, appears fairly benign in toxicity studies.
That said, while pesticides don’t make it into the thick-skinned avocado fruit, the pervasive spraying in the Mexican avocado industry is causing environmental damage and creating public health problems. Local residents who rely on lake water that receives runoff from the avocado fields exhibit high levels of liver and kidney problems. So if you can afford organic or US-grown avocados, that may be the most socially responsible option.
2. Sweet Corn
Another hyper-clean crop, sweet corn, also contained pesticide residue in fewer than one of 50 samples. And frozen corn received a perfect score — no pesticides were found in any samples. You do want to make sure to avoid BE (GMO) sweet corn, however. While the vast majority of BE corn is from varieties for feed, oil, and grain, the agronomists at Bayer (formerly Monsanto) have introduced a BE sweet corn into the market.
If you want to be sure to steer clear of BEs you may still want to opt for organic corn (or check the variety with the grower or your market produce buyer to ensure that it’s non-GMO). Other than that, pretty much any corn — organic, nonorganic, fresh, or frozen — seems to be pesticide-free.
The thick skins of pineapples appear to create an effective barrier to most pesticides. Of the six chemicals found in pineapple samples, the most common, triadimefon, appeared just under 5% of the time. Be sure to avoid the BE “pink pineapple,” which is made by Del Monte. The manufacturer proudly touts the Franken-fruit as “pinker and sweeter” than a regular pineapple — which makes me wonder: was the lack of pinkness and existing level of pineapple sweetness such a pressing problem?
Aside from saying no to pink, it seems that you’re fine with any domestic pineapple — organic or not, fresh or frozen. If opting for canned pineapple, look for some that is packed in water or organic fruit juice, not syrup.
Regular onions (that is, not green onions or scallions) also made the Clean Fifteen, whether organic or not. Despite being bombarded with a wide variety of pesticides, the majority of them are found in the outer layers and skin, which are typically removed as you peel the onion.
So as long as you peel your onions properly, your pesticide exposure will be minimal. You can still choose organic onions to protect farmworkers. But for your own consumption, any domestic onions that you peel will likely have little if any pesticide residue on the edible part.
Papayas contain few pesticide residues. With papayas, you may want to pay attention to whether they’re GMO. Most papayas grown in the US are from Hawaii. And unfortunately for fans of mother nature, 75% of these are GMO.
Originally, GMO papayas were introduced on The Big Island to combat a virus that attacked the trees. When consumers began worrying about the safety of GMOs and started demanding non-GMO papayas, growers discovered that the GMO strains had cross-pollinated with and contaminated the non-GMO strains. So if you want non-GMO papayas, stick to organic, choose known non-GMO varieties, such as Solo, or purchase imported fruit. Mexican papayas, for example, often don’t taste as sweet as the Hawaiian varieties, but are usually more affordable — and they are not GMO.
6. Sweet Peas (frozen)
Even if you’re not going to use them exclusively as an icepack, you can feel safe eating just about any variety of frozen peas — organic and nonorganic, domestic, and imported. Of the seven pesticides found on frozen peas, only one, dimethoate, appears in more than four percent of samples. And even that pesticide, which attacks insects’ nervous systems and kills them on contact, was found in only one out of eight samples, as it tends to degrade rapidly once applied.
Those happy green spears that have such an interesting effect on our pee are pretty clean even when conventionally grown. Of the nine pesticides found on asparagus, the really nasty ones appeared on less than one percent of samples tested. Any domestic asparagus is a fine choice. And frozen is also not a problem when it comes to pesticides.
8. Honeydew Melon
Honeydew growers, in California at least, have largely committed to reduced and strategic pesticide use in a system known as IPM (integrated pest management). This method sometimes includes pesticides, but quite judiciously. And it features many farming practices that reduce pest pressure, such as planting in raised beds to improve drainage and minimize root diseases, killing weeds with flame rather than chemicals, and replacing sprinklers with drip irrigation.
While the USDA doesn’t test honeydews, the FDA’s pesticide data shows about 45% of honeydew samples tested were without pesticides. Luckily, honeydews have a tough outer shell, and it’s unlikely that the inner, edible flesh would be exposed.
Despite “Kiwi” being the nickname for folks from New Zealand, the kiwifruit is also grown in the US. If your main concern is your own health, domestic kiwifruits are relatively safe. The problem is, nonorganic fruit is treated with pesticides that can be harmful to the farmworkers whose hands bring us our food. For them, in addition to acute illness immediately following exposure, pesticides are also linked to high levels of chronic disease. They can also poison groundwater and injure nonhuman animal species.
CR rated kiwifruit as “good,” which isn’t exactly a resounding vote of confidence. Their middle-of-the-road rating may be because they’re among the fruits known to have residues of the fungicide fludioxonil, which may have hormone-disrupting effects. But as long as you don’t eat the skin of the kiwi, you’ll likely be fine. However, your best bet all around is to choose organic if you can.
It’s good to know that despite non-organic kale’s dreadful rating as a source of pesticides, some members of the cruciferous clan can still put on a good show without an organic certification. Like cauliflower and broccoli, cabbage fits this bill. Of the seven most common pesticides found in cabbage by the USDA, only methomyl and flonicamid are associated with health issues. And they appear in 1.3% and 0.8% of samples, respectively.
Both domestic and imported cabbage are deemed acceptable.
By far, the most common pesticide used on mushrooms, thiabendazole, is also a pharmaceutical routinely prescribed for humans to treat pinworm and hookworm infections, among others. I’m not suggesting going on a mushroom binge if you get diagnosed with a worm infection — just letting you know that, as far as pesticides go, it’s not considered an especially harmful substance (unless you happen to be a pinworm!).
Mushrooms are kind of fun to grow, especially if you start with a kit that has everything you need. While organic is always best, you can pretty safely choose any fresh domestic mushroom, organic or not.
Out of the 17 pesticides found in cantaloupes, the five most common are considered benign for human use (although three of them are moderately to highly toxic to honeybees). Cantaloupes are typically less heavily sprayed than many other crops; the average coverage is less than two-fifths of a pound of pesticides per acre.
Mangoes are new to the Clean Fifteen list for 2022. While these tropical fruits may contain any of 11 pesticides, most are found in less than 1% of samples. The pesticide that’s found the most often on mangoes, thiabendazole, was only found, on average, 15% of the time and only in conventional fruit — either domestic or imported.
CR also rates mangoes as “very good” across the board — both conventional and organic varieties.
Watermelon is also new to the Clean Fifteen list this year, as more recent data is now available for it than a few of the former list-makers. Watermelons do have slightly more pesticides than other Clean Fifteen produce. And CR rates domestic watermelon as “good” and imported watermelon as “fair.” But luckily, most pesticides were only found in less than 1% of samples and only found on the outer rind of the fruit, not the flesh.
Around 10 different pesticides used on watermelons are harmful to bees and other pollinators, which are essential for watermelons to grow. But some farmers are beginning to reduce pesticides used on and near watermelon fields to save pollinators and improve yields. Although this news is heartening, you still have the option of buying organic watermelon, which is a lot cleaner and better for pollinators.
15. Sweet Potatoes
And finally, sweet potatoes are brand new to the Clean Fifteen list after hanging out in the Middle 19 — produce with medium pesticide contamination — for a while (along with mangoes and watermelons). According to the USDA, 19 different pesticide residues were found on conventionally produced sweet potatoes between 2016 and 2018. The vast majority of samples (although still only less than half) contained Dicloran, which is a pre- and postharvest fungicide used to prevent soft rot of sweet potatoes. If you peel your sweet potatoes, you’ll likely remove most of any pesticide residue. But if not, a good scrub with baking soda and water is a wise idea.
CR rated domestic conventional sweet potatoes as “very good” and organic as “excellent.”
Pesticide-Free Clean 15 Recipes
The Clean 15 make it easy to create a variety of cost-effective, delicious, and nutritious meals throughout the week. We’ve listed a few to get you started: the best-ever Cream of Broccoli Soup, fragrant and flavorful Roasted Cauliflower with Turmeric and Cumin, and crunchy goodness with the Collard Wraps. Here’s to staying well through clean-eating!
Beloved avocados and sweet potatoes make the Clean Fifteen list — making this unique twist on traditional avocado toast nutrient-dense sans the chemicals. Tip: Make the sweet potatoes ahead of time so this tasty and fulfilling breakfast can be assembled in minutes. Tip number two: Don’t be afraid to pile the toppings on high!
Crunchy raw cabbage and carrots are the stars of this tasty, Asian-style slaw. It makes a lovely, light meal or side dish, or add it to salads, veggie burgers or carrot dogs as a topping, or toss it with some grilled tempeh. You can also add in some of the Clean 15 fruits for a sweeter take on this simple and refreshing recipe.
The plant-based options for stuffing savory mushrooms are endless, but walnuts and lentils truly take the (plant-based) cake. They add fulfilling fats, satisfying protein, and plenty of fiber — not to mention lots of flavor — to these umami beauties that are naturally low in pesticides. Make them for the whole family as an appetizer or enjoy them solo as a meal (with a side of organic leafy greens, of course!).
Shop & Eat Smarter
I hope this article will be a useful reference whenever you shop for fresh produce. That said, I want to make one thing very clear: Even though some of the chemicals we’ve discussed are pretty alarming, please don’t make the perfect the enemy of the good. No matter what kind of produce you end up with, eating more fruits and vegetables is almost always a good thing!
And you do have means to mitigate your pesticide exposure on many fruits and vegetables by washing them thoroughly. So especially if it’s not grown organically, or in your own backyard, you may want to wash your produce. Here’s our article on how to wash produce to get rid of pesticide residues.
Tell us in the comments:
- What produce (if any) do you always make sure is organic?
- Do you grow anything yourself? If so, what strategies do you use to keep pests from doing damage?
- Did you learn anything surprising in this article? If so, what?
Feature image: iStock.com/fcafotodigital
- Pesticides in Food: What You Should Know and Why it Matters
- How to Wash Vegetables and Fruits to Remove Pesticides