A “Dirty Dozen” list from the Environmental Working Group (EWG) paints strawberries as the most dangerous piece of produce to consume because of government tests that discovered various pesticide residues, most too low to warrant regulatory action.

This comes after the same organization in 2014 encouraged people to eat strawberries because of the health benefits they contain.

The most recent “Dirty Dozen” list published by EWG includes apples, nectarines, peaches, celery, grapes, cherries, spinach, tomatoes, sweet bell peppers, cherry tomatoes and cucumbers.

The Washington D.C.-based environmental organization calls strawberries the “dirtiest” of fruit, based on information they synthesized from the U.S. Department of Agriculture’s Pesticide Data Program. The full Pesticide Data Program Report is available online.

From it the EWG claims that nearly all samples of strawberries – 98 percent of the 176 batches tested in 2014 – had detectible levels of pesticides on them.

Aside from California, which produces about 90 percent of the nation’s strawberry crop, other states that reportedly grow strawberries include Florida, Oregon, North Carolina, Washington, Pennsylvania, Michigan, New York, and Wisconsin.

U.S. strawberry producers harvested 1.5 million tons of strawberries in 2014, according to the USDA.

To arrive at its conclusions, the EWG also used the results from 703 batches of strawberries tested by the USDA in 2009.

The report says that five of the samples from 2014 had pesticide levels that exceeded the federal tolerance level. Nine samples contained pesticides not labeled for use in strawberries.

DPR tests show regulatory compliance

Information from the California Department of Pesticide Regulation (DPR), which regularly samples fruits and vegetables for dangerous levels of pesticides, says that none of the following U.S.-grown products sampled in 2014 – apples, strawberries, dry bulb onions sweet corn, oranges, head lettuce, leaf lettuce, summer squash, broccoli, mushrooms, lemons and pears – contained illegal pesticide residues.

Though not included in its “Dirty Dozen” list, EWG noted that leafy greens and hot peppers also carry toxic pesticide residue levels.

Kale, collared greens and hot peppers “do not meet traditional ‘Dirty Dozen’ ranking criteria, but were frequently found to be contaminated with insecticides toxic to the human nervous system,” according to the EWG report.

“It is startling to see how heavily strawberries are contaminated with residues of hazardous pesticides,” said EWG Senior Analyst Sonya Lunder. “Even more shocking is that these residues don’t violate the weak U.S. laws and regulations on pesticides in food.”

The EWG report did not address verified human-health impacts resulting from the consumption of these products.

According to EWG Spokesperson Shannon Van Hoesen, the point of the report was to call attention to the potential long-term health effects of consuming produce with even the smallest amount of chemical residue on them.

The report cites medical studies, including a 1993 study by the National Academy of Sciences that led Congress to pass the 1996 Food Quality Protection Act, with its conclusions about the human health hazards related to the trace amounts of pesticide residue found on produce.

According to the EWG report, strawberries were not the only food product said to contain levels of pesticide residues. Implied throughout the report is the idea that any pesticide residue contained on food products is toxic to human beings, even though science has determined acceptable levels of crop protection products on fruits and vegetables.

Based on information published by The Alliance for Food and Family Farming, a non-profit organization of organic and conventional farmers, for a human to achieve toxic results from strawberries tainted with the maximum legal residue level, a child would have to consume over 500 pounds of strawberries at a time while an adult male would need to eat over 880 pounds of strawberries at a time to suffer ill effects from the pesticide residue on those strawberries.

At the recommended serving size of one cup, this translates into over 1,500 servings for a child and more than 2,600 servings for an adult male.

The EWG also published its “Clean Fifteen” list of produce least likely to hold pesticide residues. Those include avocados, sweet corn, pineapples, cabbage, frozen sweet peas, onions, asparagus, mangoes, papayas, kiwi, eggplant, honeydew, grapefruit, cantaloupe and cauliflower.

Key findings in the EWG report include:

Industry Reactions

The California Strawberry Commission (CSC) said the EWG report fails to factor in science suggesting that “organic and conventional strawberries are safe to eat and pesticide residues do not pose a safety concern.”

The CSC further points out that in 2014 the EWG named conventionally-grown strawberries as a “best food” for the positive health benefits strawberries have.

“Strawberries are considered a nutrient dense food, and are high in Vitamin C, a good source of fiber, plus provide essential potassium, folate, and antioxidants,” writes the CSC in a statement reacting to the EWG report. “While there are numerous studies showing the health benefits of eating berries, including improved brain and cardiovascular health, a new study found that strawberry consumption may also positively impact insulin response in the body.  Insulin response can be a factor in the development of Type 2 diabetes.”

Charlotte Fadipe, spokesperson for California DPR, said California strawberry farmers have proven to be responsible in their use of labeled pesticides as none of the 108 samples tested in 2014 contained illegal residue levels.

DPR inspectors regularly test produce from grocery stores, farmers markets and other locations where fruits and vegetables are sold.