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Pesticides in foods: Environmental Working Group's clean and dirty lists


AP Photo/Larry Crowe

Pesticides are frequently used on fruit and vegetable crops. How do you know which ones may contain pesticides? Buying certified organic is one way to avoid pesticides. But now you can do something else. Take a look at Environmental Working Group's Dirty Dozen and Clean Fifteen lists to help you choose fruits and vegetables at any grocery store.

Environmental Working Group (EWG) released a Shopper's Guide to Pesticides which lists pesticide information for 50 frequently purchased fruits and vegetables. EWG researched results of testing by the U.S. Department of Agriculture (USDA) and the U.S. Food and Drug Administration (FDA). The Dirty Dozen were foods for which a large percentage of tested positive for pesticides, in some cases several pesticides. The Clean Fifteen were foods for which a low percentage of samples tested for pesticides.

How did EWG determine the rankings of the foods? "The Shopper's Guide to Pesticides ranks pesticide contamination for 50 popular fruits and vegetables based on an analysis of 96,000 tests for pesticides on these foods, conducted from 2000 to 2008 by the USDA and the FDA. The 49 fruits and vegetables analyzed in the guide are the top 49 most consumed fruits and vegetables, as reported by the USDA, with a minimum of 100 pesticide tests between 2000 and 2009. Nearly all the studies on which the guide is based tested produce after it had been rinsed or peeled," according to the EWG methodology description.

  • The vegetables least likely to test positive for pesticides are onions, sweet corn, sweet peas, asparagus, cabbage, eggplant and sweet potatoes. Asparagus, sweet corn, and onions had no detectable pesticide residues on 90% or more of samples.
  • Fewer than 10 percent of pineapple, mango, and avocado samples showed detectable [pesticide residues], and fewer than one percent of samples had more than one pesticide residue.
  • Of the 12 most contaminated foods, 7 are fruits: peaches, strawberries, apples, domestic blueberries, nectarines, cherries, and imported grapes. More than 96% of peaches tested positive for pesticides, followed by nectarines (95.1%) and apples (93.6%).
  • Nearly 85 percent of celery samples contained multiple pesticides, followed by sweet bell peppers (61.5 percent) and collard greens (53.2 percent).

What can you do? Buying certified organic fruits and vegetable can be difficult and expensive, particularly in Chicago-area grocery stores. Stores like Whole Foods have many organic options, and other major chain stores like Jewel and Dominick's are offering more organic options now than they have in the past. Another option is to consider buying organic for the Dirty Dozen, and buy conventionally-grown options for the Clean 15.

EWG posts the full list of fruits and vegetables that were tested. They also post some background information about why and how to avoid pesticide exposures. Children may be more susceptible to negative effects of pesticides for several reasons, and EWG urges parents to consider choosing foods carefully for children.

Pesticide use on crops and pesticide content of foods is an ongoing concern for environmental health. Scientists continue to evaluate and monitor the benefits and risks of pesticide use on a large scale on food crops. Environmental health scientists and toxicologists continue to study potential health effects of pesticides, and what levels of pesticide exposures may reach a level of concern. The EWG report summarized finding for the presence of pesticides and which ones were detected, but did not discuss the amounts of pesticides found.

As information continues to accumulate, you can use this EWG resource guide as a starting point to make choices to minimize your and your family's exposures to pesticides.

Suggestions, comments, questions? Anything about environmental health that you would like to know about? Email your Chicago Environmental Health Examiner at Follow me on Twitter @chicagoenviron.


  • suspicious 5 years ago

    these tests were performed by the FDA and USDA?!?!?! i think that represents a biased perspective.

  • Marisa 5 years ago

    The important question regarding reliability of data would be how many samples were tested, and whether tests were repeated in more than one lab. But I am curious as to which direction you think the bias would go--underestimating or overestimating the amount of pesticide?

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