Should you be worried about pesticide residues on specific fruits and vegetables? The Environmental Working Group (EWG), a U.S.-based environmental advocacy group, believes you should be, and has released the latest version of its annual “Dirty Dozen” list, representing the 12 fruit and vegetable commodities alleged to contain the greatest relative levels of pesticides. Are such rankings validated by a careful examination of scientific evidence? Absolutely not. Should you continue to try to eat more fruits and vegetables? Absolutely!

Since its release in June 2011, the list has drawn widespread media attention and consumers have been bombarded with headlines such as “An apple a day … means you’re eating plenty of the most contaminated fruit;” “Don’t like pesticides? Better avoid these fruits and veggies;” and “Beware of pesticides in fruits and vegetables.”

According to the EWG, consumers should purchase organic forms of the commodities on the “Dirty Dozen” list or consume fruits and vegetables on their “Clean Fifteen” list, which they have found to contain the lowest relative pesticide levels. However, the benefits of eating fruits and vegetables, regardless of how they were produced, far outweigh the risk. Eating the organic forms of the fruits and vegetables on either the Dirty Dozen or the Clean Fifteen lists is fine, if that is your preference, but read on to understand why eating the conventional forms is a safe choice too.

To put things in perspective, let’s take a step back in time. The 16th century Swiss physician Paracelsus developed the first principle of toxicology with his assertion that “the dose makes the poison.” To paraphrase Paracelsus, it is the amount of exposure to a chemical that determines the potential for harm, and not simply its presence or absence. The EWG rankings do not consider actual consumer exposure, but rather reflect a relative ranking of six “contamination indicators.” These indicators are heavily skewed to indict commodities where findings of the presence of residues of multiple pesticides were more common. Such findings, however, are not appropriate to justify the recommendation to avoid conventional or consume only the organic form of specific types of produce. Such a recommendation can come only after exploring the risk of actual exposure to the pesticide residue poses to human health. After all, organic farming uses pesticides, too.

While the EWG did not estimate consumer exposure to pesticides on its “Dirty Dozen” list for reasons that will be apparent below, this work has been done. Just prior to the release of EWG’s Dirty Dozen list, a paper authored by me and my doctoral student Josh Katz at the University of California, Davis was published in the Journal of Toxicology. This paper examined the same U.S. Department of Agriculture (USDA) pesticide residue data used by EWG to develop its rankings and developed consumer exposure estimates for each of the 10 most frequently detected pesticide residues on each of the twelve fruit and vegetable commodities. The paper also evaluated the methodology EWG used to determine its rankings.