The Environmental Working Group (EWG) https://www.ewg.org/ publishes a "Dirty Dozen" list that ranks the most popular fruits and vegetables based on their pesticide residue levels.
By analyzing pesticide residue data from more than 36,000 samples tested by the USDA and FDA, this year EWG found a total of 178 different pesticides on fresh produce samples tested - residues that remain even after items are washed and, in some cases, peeled.
Here's a list of which fruits and veggies you might want to be wary of at the grocery store.
Strawberries: For the second year in a row, strawberries have been named the top carrier of pesticides in produce. In EWG's findings, 99 percent of the strawberries tested by federal officials contained detectable pesticide residues. Of those strawberry samples, 29 percent included residues of 10 or more pesticides while some contained as many as 21 different pesticides.
Spinach: Three-fourths of samples tested were contaminated with a neurotoxic bug killer that's banned from use on food crops in Europe. With an average of 7 pesticides found on every conventionally grown spinach sample collected in 2015, you'd be wise to thoroughly rinse the leaves before chowing down.
Nectarines: Last year, more than 98 percent of nectarines tested positive for multiple pesticide residues. Since Americans eat nearly 8 pounds of the fruit each year, according to EWG, this is a special concern for the organization.
Apples: According to the report, "pesticides are created expressly to kill living organisms -- insects, plants, and fungi that are considered "pests." Many pesticides pose health dangers to people. These risks have been confirmed by independent scientists and physicians across the world."
Peaches: The USDA summarized its own testing from 2014 and concluded that "overall pesticide residues found in foods are at levels below the tolerances set by the U.S. Environmental Protection Agency." But keeping pesticides at a legal level may not be enough for some customers, which is why EWG stresses buying organic produce.
Pears: According to tests by the USDA, the amount of pesticide residues on pears has more than doubled since 2010, with more than 50% of pears tested showing residues of 5 or more pesticides, and some had a whopping 20, including fungicides.
Cherries: "Fruits and vegetables are important for your health," Sonya Lunder, EWG Senior Analyst, said in a release. "But for those on the Dirty Dozen, we recommend buying the organic versions if you want to avoid pesticides on your food."
Grapes: "Even low levels of pesticide exposure can be harmful to infants, babies, and young children, so when possible, parents and caregivers should take steps to lower children's exposures to pesticides while still feeding them diets rich in healthy fruits and vegetables," said Dr. Philip Landrigan of the Mt. Sinai School of Medicine.
Celery: Opt for veggies on the list of produce least likely to contain pesticide residues, such as corn, avocados, cabbage, onions, and frozen sweet peas.
Tomatoes: Though cherry tomatoes dropped down to #14 on this year's list, the full-grown variety still remains in the top 10. A release from EWG warns that "the pesticide industry and chemical agriculture maintain that pesticides on produce are nothing to worry about, but doctors and scientists strongly disagree."
Sweet Bell Peppers: So should we stop eating these produce varieties completely? Many researchers say no based on the amount of pesticides animals can tolerate in animal studies and still live a full lifespan.
Potatoes: These have displaced cucumbers from the top 12 in this year's list.