Strawberries again top 2018's 'Dirty Dozen' fruits and veggies

Once again, strawberries top the list of the 12 "dirtiest" fruits and vegetables, according to the United States-based Environmental Working Group.

Every year since 2004, the group - a nonprofit, nonpartisan environmental organisation - ranked pesticide contamination in 47 popular fruits and vegetables for its Shopper's Guide to Pesticides in Produce.

Pesticides include a wide array of chemicals that kill unwanted insects, plants, molds and rodents.

Spinach is the second dirtiest item on the "Dirty Dozen" list, followed by (in order of contamination) nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery, potatoes and sweet bell peppers. Each of these foods tested positive for pesticide residues and contained higher concentrations of pesticides than other produce.

In fact, nearly 70% of conventionally grown - non-organic - produce samples were contaminated, the tests indicated.

The shopper's guide is based on results of tests by the US Department of Agriculture and the Food and Drug Administration on more than 38,800 non-organic samples. The Environmental Working Group looks at six measures of contamination including the average number of pesticides found on samples and the average amount of pesticides found.

When testing samples, the USDA personnel wash or peel produce to mimic consumer practices.

A single sample of strawberries showed 20 pesticides, the report indicated. More than 98 per cent of strawberries, spinach, peaches, nectarines, cherries and apples tested positive for at least one pesticide residue. And, on average, spinach samples had 1.8 times as much pesticide residue by weight than any other crop.