Air Date: Week of January 24, 2025

Strawberries are ranked number one on the Dirty Dozen list, indicating that they are on average the most contaminated from pesticides when bought conventionally. (Photo: Suzanne Schroeter, Flickr, CC BY-SA 2.0)

Not all conventionally grown fruits and vegetables are loaded with high levels of harmful pesticides. To help consumers make efficient choices in the produce aisle, every year the Environmental Working Group puts together two lists, the “Dirty Dozen” and the “Clean Fifteen.” EWG Toxicologist Alexis Temkin talks to Host Steve Curwood about how to use them during grocery trips.

Transcript

DOERING: It’s Living on Earth, I’m Jenni Doering.

CURWOOD: And I’m Steve Curwood.

Though there are no human studies that precisely correlate eating more organic food with reduced risk of cancer, pesticide exposure is certainly not good for our health. But there are tradeoffs. Organic food has limited availability and can cost more. The good news is that not all conventionally grown fruits and veggies are loaded with high levels of pesticides. To help consumers make efficient choices in the produce aisle, every year the Environmental Working Group puts together two lists, the “Dirty Dozen” and the “Clean Fifteen.” Here to explain what these lists mean and how to use them during grocery trips is Alexis Temkin, a Senior Toxicologist at the Environmental Working Group. Welcome to Living on Earth Dr. Temkin!

TEMKIN: Thank you so much for having me, happy to be here.

CURWOOD: So, the Dirty Dozen and the Clean Fifteen. How did the Environmental Working Group put these two lists together? What makes one food dirty and one food clean?

TEMKIN: Yeah so, this is part of a broad consumer guide that we use called the Shoppers Guide to Pesticides and Produce, and we actually look at around 46 different fruits and vegetables for pesticide residues. And these data come from federal agencies that are testing fruits and vegetables on store shelves for the presence of pesticides. And we essentially analyzed that data to look at which fruits and vegetables have the most pesticides, whether that's the number of pesticides found, the concentrations, the detection frequencies of different fruits and vegetables and the ones that come out on top are claim the Dirty Dozen, things like strawberries, spinach, kale, grapes and things that come out on the bottom as the least contaminated, the Clean Fifteen, things like avocados, sweet corn, pineapple and onions, those are the Clean Fifteen.

CURWOOD: So how is this order determined? I mean, for example, I see that strawberries are ranked number one on the Dirty Dozen.

TEMKIN: We use, as I mentioned, data that's actually generated from the United States Department of Agriculture, primarily, as well as from the FDA. There's a program at the USDA called the Pesticide Data Program. We've developed a tool to rank fruits and vegetables based on the analysis of that data. So, it's using six different indicators of pesticide contamination. So we look at for each of these different commodities, you know, whether that's strawberries or apples or blueberries, we look at the percent of those samples that have detectable pesticides, the percent of samples that have two or more, because actually a lot of fruits and vegetables can have, in some cases, up to a dozen or so different pesticides detected, the average number of pesticides on a single sample, the average amount of pesticides found, the total number found on a single sample, and the total number found on the crop. So, there's a few different ways we analyze this, and then based on how you rank in each of those ultimately determines how you rank in the final sort of list of those 46, which we break up right into 12 and 15.

CURWOOD: I'm learning something here because I thought strawberries were at the top of the Dirty Dozen, because you just can't wash the pesticides off of strawberries.

TEMKIN: This is a great point, and I'm so glad you're bringing it up, because the way that the data are generated from the USDA actually involves a washing step before they test for pesticides. So, part of this program in terms of pesticide residue analysis from the USDA is actually designed to try and mimic consumer exposure to some degree. So, fruits and vegetables are typically washed for some period of time, you know, akin to how somebody might do it at home. Fruits and vegetables that need to be peeled, like a banana or a citrus or something like that, are peeled before they're analyzed. So, you definitely don't get rid of all of your pesticide exposure just by washing. There's still a considerable amount of pesticide left over, although washing is something we definitely recommend to at least remove some possible pesticide residue.

CURWOOD: Let's cut to the basic question here, why should people be concerned with pesticides in their diet, especially those of us who've been eating nonorganic produce our whole lives, maybe even today.

TEMKIN: Yeah, well so fruits and vegetables definitely offer an immense amount of health benefits. So, it's something that we always want to emphasize, that it's really important to continue eating fruits and vegetables, even of conventionally grown produce. You know, the reason we put out this guide is so that if you're shopping for items on the Dirty Dozen, if you're a strawberry lover, for instance, it might be worth considering buying those organic to reduce that pesticide exposure. And then this Clean Fifteen list are sort of low in pesticide residue, even through conventional. So, it's a way to sort of balance perhaps buying organic and buying conventional. Because, of course, that can be difficult, but some of the reasons you might wanna be concerned are that exposure to pesticides have been linked to a variety of health effects. There are a few neurotoxic pesticides that can be really important in terms of their impact on developing brains. Some mixtures of pesticides have also been associated with reproductive harm, like actual impacts on fertility, and in some cases, we've also seen pesticides associated with cancer risk. And really the way that these pesticides are regulated, are looking at them one at a time, but we know from looking at this data about pesticides on food, you know, there's about 250 different pesticides detected on food, so the way we're exposed are these mixtures of pesticides. And we sometimes know that when you're exposed to multiple pesticides, there can be different health effects at lower doses than if you were just exposed to one, which is how the regulatory agencies really regulate them.

CURWOOD: Understanding all this, what should people do? What should we do as consumers?

TEMKIN: I mean, I think it's understandable that this is a balancing act, and it is also how we live our lives, and that can be really hard to sort of balance all these different things and worry, how much am I exposed to? How concerned do I have to be? And I think that's exactly why this shoppers guide, or the Dirty Dozens, came into existence, was just to hopefully try and optimize that balance so that there's this beneficial experience of eating a lot of fruits and vegetables, which we know has been studied over and over again in the literature, and is extremely important, it can be really health protective. There are some studies that show sometimes, if you look at the health benefits on cardiovascular disease by eating fruits and vegetables, one study actually showed that, well, if most of your vegetable consumption comes from high residue foods that protective benefit gets a little bit weaker. So, we wanna sort of optimize how you get the benefits of both, and one way to do that is by reducing exposure to pesticides. And you could eat an organic diet all the time, but that's really just not doable for most people. I certainly can't even do that. So, we recommend buying organic options of items on the Dirty Dozen if they're things that you love to eat. You know, for instance, I personally don't love strawberries. I don't eat them all that often, but I do love other things on the Dirty Dozen that we try to buy organic, and then the Clean FIfteen are also really wonderful fruits and vegetables that just have low pesticide residues.

CURWOOD: Wait a minute, you're not into a strawberry on a hot June day that's just so sweet and dripping with the beginning of summer essence?

TEMKIN: That does sound wonderful, actually, when you put it that way, strawberries in season are a special, special treat.

CURWOOD: What about the money? Organic sometimes, but not always, costs more. Someone listening to us thinking about that, you know, budget is a little tight. How far should they reach to include organic in that budget? Do you think?

TEMKIN: I think it's a hard question. I think that's really a personal decision. I would, I guess, prioritize, as I mentioned, eating fruits and vegetables first over processed foods, and then if the budget allows really shifting towards organic options on the Dirty Dozen, or really looking at just more of those conventional options on the Clean Fifteen, you know, but like avocados, kiwi, asparagus, mushrooms, sweet potatoes, carrots, I don't know, that sounds like a lovely stew.

CURWOOD: And what's your favorite on your list of the Clean Fifteen? What will you be cooking tonight, do you think?

TEMKIN: I will probably be cooking something with sweet potatoes, which are on the Clean Fifteen list, and mushrooms… And onions!

CURWOOD: Okay, there you go. It'll smell good.

TEMKIN: Yes, exactly.

CURWOOD: Alexis Temkin is a senior toxicologist at the Environmental Working Group, the organization that publishes the Dirty Dozen and Clean Fifteen. They change it every year. Thank you so much for taking the time with us.

TEMKIN: Thank you so much for having me.

[MUSIC: The Beatles, “Strawberry Fields Forever” on YouTube originally on Magical Mystery Tour, by John Lennon and Paul McCartney, Universal Music Group]

CURWOOD: Hey, by the way Jenni, you’ve shown us there is a great way to get organic food, even fancier stuff like mushrooms, and it’s called do it yourself.

DOERING: Yeah, that’s right! It did take a year before harvest, but Aynsley O’Neill and I inoculated a log, we left it outside in my backyard and then we were rewarded with organic shitake mushrooms. And there was no weeding required!

CURWOOD: Yeah, like almost everyone I get almost all of our family food at the grocery store but just using pots and a small patch we’ve grown organic tomatoes, peppers, chives, and even huge bushes of basil. We also have a raspberry patch, and my daughter has a bed for strawberries, though chipmunks are quick to steal ‘em.

DOERING: Oh, I know! The squirrels taking my garlic… Critters can be a problem of course, and not everybody has a yard, but you can grow things like lettuce and kale pretty easily in a window box. Best of all, you know, whether is a big project or just a few pots, gardening can get us outside, rewards us with a bit of a workout and tunes us to the seasons. It’s still winter here in New England, with a lot of snow on the ground, but my garlic is already coming up!

 

Links

Environmental Working Group’s 2024 Shopping Guide to Pesticides in Produce: Read here

Environmental Working Group’s 2024 Clean Fifteen List: Read here

Frontiers | “Pesticides Potentially as Bad as Smoking for Increased Risk in Certain Cancers”

CNN | “Toxic ‘Forever Chemicals’ Found in Pesticides Used on Food, in Homes and on Pets, Study Finds”

CBS | “Pesticides Pose a Significant Risk in 20% of Fruits and Vegetables, Consumer Reports Finds”