EWG's Clean Fifteen™ list, those fruits and vegetables with the least pesticide load, consists of corn, onions, pineapples, avocados, cabbage, frozen sweet peas, papayas, mangoes, asparagus, eggplant, kiwi, grapefruit, cantaloupe, sweet potatoes and mushrooms.
"When given a choice, more consumers are choosing organic fruits and vegetables or using EWG's Shopper's Guide to find an easy affordable way to avoid toxic chemicals," said Sonya Lunder, an EWG senior analyst. "They want to eat a diet rich in fruits and vegetables without eating too many pesticides. And they want to support local farms and agriculture that is better for the environment."
EWG's Shopper's Guide to Pesticides in Produce, now in its 9th year, ranks pesticide contamination on 48 popular fruits and vegetables, based on an analysis of more than 28,000 samples tested by the U.S. Department of Agriculture and federal Food and Drug Administration.
EWG researchers compile the Shopper's Guide and the Dirty Dozen and Clean Fifteen lists from pesticide residue tests conducted by USDA and FDA scientists, who made public their most recent round of results earlier this year. Since government scientists wash or peel samples before testing them, pesticide measurements reflect the likely pesticide loads of produce when people eat it. EWG's ranking uses six measures of pesticide hazards, among them, the number of pesticides detected on a crop and the percent of samples testing positive.
For the second year, EWG has expanded the Dirty Dozen™ with a Plus category to highlight two crops - domestically-grown summer squash and leafy greens, specifically kale and collards. These crops did not meet traditional Dirty Dozen™ criteria but were commonly contaminated with pesticides exceptionally toxic to the nervous system.
In the most recent USDA tests for kale and collards, conducted in 2008, some samples were found to be contaminated with organophosphate pesticides. Organophosphate pesticides are potent neurotoxins that can affect children's IQ and brain development, even at low doses. Over the past decade organophosphates have been withdrawn from many agricultural uses and banned for home pesticide use but still be applied to certain commercial crops.
Banned organochlorine pesticides were detected on nearly 20 percent of the samples of zucchini and crookneck squash in 2008. Imported summer squash were cleaner. Most organochlorine pesticides were widely applied in the 1940s through 1970s but withdrawn from use after studies revealed them to be highly toxic to people and wildlife. They are extremely persistent in the environment and still pollute produce grown in contaminated soils.
Results remained troubling for some baby foods purchased in American stores in 2011. Green beans canned for baby food tested positive for five pesticides, including the toxic organophosphates methamidophos and acephate, detected on 14 and 13 percent of samples respectively. EPA and producers have voluntarily agreed to remove these two chemicals from agriculture due to health concerns. Pear samples tested positive for 11 pesticides, including iprodione, deemed to be probable carcinogen and not registered for use on pears.
Pesticides are toxic by design and created expressly to kill living organisms -- insects, plants and fungi that are considered "pests." Many pesticides pose health dangers to people and have been linked to brain and nervous system toxicity, cancer, hormone disruption, skin, and eye and lung irritation.
Last year, the American Academy of Pediatrics, which represents more than 60,000 pediatricians, for the first time adopted an official position warning doctors and parents that pesticide exposures from food are potentially dangerous to children's health.
"By following EWG's Shopper's Guide and advice, consumers can feel confident they can buy foods with consistently lower overall levels of pesticide contamination," said Lunder.
EWG advises people who want to avoid genetically engineered food as well as pesticides to buy organically-raised produce. U.S. law does not require labeling of GE foods. Zucchini, Hawaiian papaya and some varieties of sweet corn may be genetically modified.