Apples once again topped the 2014 “Dirty Dozen” list of the most pesticide-contaminated produce for the fourth year in a row.

The Environmental Working Group (EWG), a watchdog organization in Washington, D.C., released its report Tuesday in an effort to help consumers reduce the pesticide intake in their diets.

The group ranks 48 of the most popular produce on an analysis of 32,000 samples tested by U.S. Department of Agriculture and the U.S. Food and Drug Administration.

The report also found that leafy greens, such as kale and collard greens, and hot peppers were frequently contaminated with insecticides that are particularly toxic to human health.

The report also found every sample of nectarines tested and 99 per cent of apple samples tested positive for at least one pesticide residue. A single grape tested positive for 15 pesticides, while samples of celery, cherry tomatoes, snap peas and strawberries contained 13 different pesticides apiece.

The full “Dirty Dozen” list:

  1. Apples
  2. Strawberries
  3. Grapes
  4. Celery
  5. Peaches
  6. Spinach
  7. Sweet bell peppers
  8. Nectarines
  9. Cucumbers
  10. Cherry tomatoes
  11. Potatoes
  12. Snap peas

The report also released some good news for shoppers, a list known as the “Clean Fifteen,” which consists of the produce with the least amount of pesticides.

Avocadoes topped the list with only one per cent of samples showing pesticides.

The full “Clean Fifteen” list:

  1. Avocadoes
  2. Corn
  3. Pineapples
  4. Cabbage
  5. Frozen sweet peas
  6. Onions
  7. Asparagus
  8. Mangoes
  9. Papayas
  10. Kiwi
  11. Eggplant
  12. Grapefruit
  13. Cantaloupe
  14. Cauliflower
  15. Sweet potatoes

The report found that no sample from the “Clean Fifteen” list contained more than four types of pesticides.