Researchers: You could be eating "dirty" produce - WAFF-TV: News, Weather and Sports for Huntsville, AL

The produce you eat might be dirty even after you wash it.

The Environmental Working Group's annual "Dirty Dozen" report named the fruits and vegetables that showed the highest amount of pesticide residue.

In addition to the first dozen foods, researchers added a dirty "plus" category to highlight crops that did not meet traditional Dirty Dozen criteria but are still often contaminated with organophosphate insecticides. Those insecticides are toxic to the nervous system.

Environmental Working Group's Dirty Dozen foods included: apples, celery, sweet bell peppers, peaches, strawberries, imported nectarines, grapes, spinach, lettuce, cucumbers, domestic blueberries and potatoes. Green beans and kale were also listed in the dirt dozen plus list.

Researchers also compiled a list of the cleanest fruits and vegetables. These "Clean 15" produce items have the least amount of pesticide residue: onions, sweet corn, pineapples, avocado, cabbage, sweet peas, asparagus, mangoes, eggplant, kiwi, domestic cantaloupe, sweet potatoes, grapefruit, watermelon and mushrooms.

Researchers at The Environmental Working Group report based their list on pesticide residue data collected by the U.S. Department of Agriculture and the Food and Drug Administration. The samples were tested as they would normally be eaten- after being washed or peeled.

In order to minimize possibly harmful pesticide exposure, experts recommended buying organic produce. If that seems too expensive, another option is to buy organic versions of the "Dirty Dozen" items and buy the traditionally farmed versions of the "Clean 15."