WASHINGTON, March 22 — Kale may not be as virtuous as long thought. Because in a new report ranking the most pesticide-laden foods, the hearty leafy green has emerged as one of the "dirtiest” foods you can find in the supermarket.

It was a surprise finding for the Environmental Working Group, which released their latest edition of their annual Shopper’s Guide to Pesticides in Produce report in the US.

Researchers found that more than 92 per cent of kale samples carried two or more pesticide residues, while a single sample could contain up to 18 different kinds of residues.

The most frequently detected pesticide found on nearly 60 per cent of all kale samples, was Dacthal, or DCPA — classified by the Environmental Protection Agency since 1995 as a possible human carcinogen, and prohibited for use in Europe since 2009.

On the list of dirty dozen foods, kale is ranked third after strawberries and spinach, frequent offenders on the group’s annual ranking.

"We were surprised kale had so many pesticides on it, but the test results were unequivocal,” said EWG Toxicologist Alexis Temkin in a statement. 

"Fruits and vegetables are an important part of everyone’s diet, and when it comes to some conventionally grown produce items, such as kale, choosing organic may be a better option.”

Here are the "dirtiest foods” at the grocery store:

1. Strawberries 2. Spinach 3. Kale 4. Nectarines 5. Apples 6. Grapes 7. Peaches 8. Cherries 9. Pears 10. Tomatoes 11. Celery 12. Potatoes

At the other end of the spectrum, relatively few pesticides were found on these foods, named the "Clean Fifteen”:

1. Avocados 2. Sweet corn 3. Pineapples 4. Frozen sweet peas 5. Onions 6. Papayas 7. Eggplants 8. Asparagus 9. Kiwis 10. Cabbages 11. Cauliflower 12. Cantaloupes 13. Broccoli 14. Mushrooms 15. Honeydew melons

Researchers emphasise that eating fruits and vegetables is important for a healthy diet. The list was created to help consumers reduce their pesticide exposure and suggests which produce they should buy organic. — AFP-Relaxnews