April 10, 2018 -- Strawberries once again top the annual ''Dirty Dozen" list of produce found with the most pesticides.
And once again, experts not involved in the report say they worry the list will discourage people from eating fruits and vegetables, especially people on budgets who view higher-priced organic produce as unaffordable.
The Environmental Working Group (EWG), a nonprofit organization focused on human health and the environment, issues the “Dirty Dozen” report each year. EWG researchers this year found that more than 98% of samples of strawberries, along with spinach, peaches, nectarines, cherries, and apples, had residue of at least one pesticide. A single sample of strawberries had 20 different pesticides.
It's no surprise that strawberries again lead the list, says Sonya Lunder, MPH, senior analyst with EWG and a researcher of this year's report. Over the years, she says, "the list itself doesn't change much.''
This year's "Dirty Dozen" includes the same 12 fruits and vegetables as last year's list, with a few trading places. The 2018 list, in descending order, is:
The report also includes the EWG's "Clean 15'' list, the produce least likely to contain pesticide residue. The 2018 list is nearly identical to last year's, with sweet corn and avocados trading places for first and second and grapefruit knocked out of the No. 15 spot in favor of broccoli.
- Sweet corn
- Frozen sweet peas
- Honeydew melon
About the Rankings
EWG researchers create the rankings based on laboratory tests done by the FDA and the U.S. Department of Agriculture's Pesticide Testing Program. The analysis for 2018 included nearly 39,000 samples. The tests found 230 different pesticides and pesticide breakdown products on the samples. Breakdown products are substances that form when pesticides mix with the environment. They can also be toxic.
To compute the ranking, researchers combined six different measures of contamination and arrived at a composite score. The measures include the percent of samples with detectable pesticides, the total number found on the crop, and the maximum number of pesticides on a single sample.
Lunder says the lists can help people to consider buying certain organic fruits and vegetables to reduce pesticide exposure.
The government labels as “organic” food grown without synthetic chemicals or fertilizers, genetic engineering, radiation, and sewage sludge.
She acknowledges that organic foods are more expensive and could be a barrier to some, and says people should not cut back on eating fruits and vegetables if they can’t afford organic.
She says it may be more important to buy organic foods at certain times. Families with young children may want to avoid produce with higher pesticide residues, and she notes that research has found a link between certain pesticides (such as chlorpyrifos) and children's brain development and behavior.
Women trying to get pregnant may also want to eat more organic produce, Lunder says. In one study, women undergoing fertility treatments who ate more fruits and vegetables with high-pesticide residues were less likely to become pregnant. Research on men's produce eating habits and reproductive health have yielded mixed conclusions. Some research has found men who eat higher-pesticide produce had worse reproductive health, Lunder says, while other research has found no link.
Carl K. Winter, PhD, food toxicologist and vice chair of food science and technology at the University of California Davis, says the amounts of pesticides found on produce are ''tiny."
To look at health risks in people, Winter says, three components are necessary: ''the actual amount of pesticide detected, the amount of food consumed by the individual, and the toxicity of the pesticide."
Based on the report, he says, "I worry that people are becoming concerned when they should not be."
Getting a food-borne illness from unwashed produce is a more realistic worry, he says.
Teresa Thorne, executive director of the Alliance for Food and Farming, an industry group representing farmers who grow both organic and conventional fruits and vegetables, says ''the report is not science-based." She points out that much of the research finding benefits to a diet rich in fruits and vegetables has been done on conventionally grown produce, not organic.
Tips on Washing Produce
It's important to wash produce in plain tap water, Winter says.
Experts agree it probably won't get rid of all the pesticide residue. But it will help reduce viruses and bacteria on the produce, Winter says. That's important to also avoid food-borne illness, he says.
In the U.S., nearly half of food-borne illness is linked to germs on fresh produce, the CDC says.