Pesticide Contamination in Food

Just how contaminated are conventionally grown fruits and vegetables? The nonprofit organization Environmental Working Group (EWG) took on the challenge and created The Shopper’s Guide to Pesticides, which ranks the pesticide contamination for popular fruits and vegetables based on an analysis of tens of thousands of tests for the contaminants conducted by the US Department of Agriculture (USDA) and the Food and Drug Administration (FDA). All of the samples are taken after the produce has been rinsed or peeled, so the information reflects the amount of contaminants most likely to be on the produce when it is consumed.

The most recent edition (seventh) of the Shopper’s Guide to Pesticides, released in June 2011, includes updated information about 53 fruits and vegetables and their pesticide load based on an analysis of 51,000 tests for pesticides conducted from 2000 to 2009 by the USDA and the FDA. The EWG analysts evaluated these data and compiled the Dirty Dozen list (12 most contaminated fruits and vegetables) and the Clean 15 list (the least contaminated fruits and vegetables).

Some significant changes from the previous year’s edition include the addition of cilantro (at no. 13), which had never been tested by the USDA until now. The analysis showed 33 unapproved pesticides on 44 percent of the cilantro samples tested. This is the highest percentage of unapproved pesticides ever found on any items included in the Shopper’s Guide since the Environmental Working Group began documenting the data in 1995. Other changes were seen in apples, which moved up to the number one spot as the most contaminated produce, and mushrooms, which are new to the “Clean 15” list.

Consumers are exposed to a wide range of pesticides on their food, and these chemicals can be extremely toxic to human health. Pesticides, herbicides, fungicides, and other chemicals used on food crops have been linked to cancer, nervous system disorders, hormone system disruption, and reproductive system abnormalities. Yet despite these health dangers, toxic chemicals are still used on non-organically grown food crops. According to the EWG, consumers can reduce their pesticide consumption by about 80 percent if they avoid conventionally grown produce that appears on its Dirty Dozen list. Eating fruits and vegetables from this list exposes people to an average of 10 pesticides per day, compared to two per day when they choose produce form the Clean Fifteen list. Choosing organic produce is the optimal choice, because it dramatically reduces pesticide exposure. When organic is not an option, choosing alternatives from the least contaminated list is suggested.

12 Most Contaminated Fruits and Vegetables (beginning with the worst) 1 Apples top the list of the most contaminated fruits and vegetables, with 97.8 percent of the 700 samples testing positive for pesticides. Two or more pesticide residues were detected on 92 percent of apples, and all together 56 different pesticides were found on the apples tested. Apple peels contain lots of important nutrients, so peeling a conventionally grown apple is like throwing away much of its nutrition. Choose organic. 2 Celery lost its number one spot from the last edition of the guide, but the samples still showed that 96 percent tested positive for pesticides. Nearly 90 percent of celery samples had multiple pesticides, and one celery sample was contaminated with 13 different chemicals. It is difficult to wash off pesticide residue from celery, so organic celery is recommended. 3 Strawberries had up to 13 pesticides detected on a single sample. One of the pesticides approved for use on strawberries is methyl iodide, which was recently approved by the California Department of Pesticide Regulation (the state where 80% of strawberries are grown). Methyl iodide causes cancer in rodents, and EPA notes that chronic inhalation of the pesticide may damage the human central nervous system. Long-term skin contact can cause burns in animals and people. 4 Peaches were found to be treated with more pesticides—57 different chemicals—than any other fruit or vegetable in the study. Nearly 86 percent of peaches contained two or more pesticide residues. The 2008 USDA Pesticide Data Program found eight carcinogenic pesticide residues on peaches. Skinning a peach can help, but organic is best. 5 Spinach has the unfortunate distinction of presenting a greater risk of pesticide exposure than any other greens. The 2008 USDA Pesticide Data Program found five known or probable carcinogenic pesticide residues on spinach. 6 Imported nectarines were the only item in the study for which 100 percent of the samples were contaminated with pesticides. Nearly 91 percent of imported nectarines also had two or more pesticide residues. The 2008 USDA Pesticide Data Program found five known or probable carcinogenic pesticide residues on nectarines. 7 Imported grapes are more likely to be contaminated than domestically grown grapes. Because they have thin skins, it is very difficult to wash away contaminants from grapes. Imported grapes had 14 different pesticides detected on a single sample. Both organic grapes and organic wine are recommended. 8 Bell peppers had multiple pesticide residues in nearly 70 percent of cases, and a single sample of the vegetable revealed 11 different chemicals. This is not surprising, given that bell peppers can be treated with up to 63 different chemicals. The 2004 USDA Pesticide Data Program found nine known or probable carcinogenic pesticide residues on bell peppers. 9 Potatoes may grow underground but that does not prevent them from becoming contaminated with pesticides. Nearly 92 percent of potatoes tested positive for pesticides, and up to 37 different chemicals can be used to treat potatoes. The 2008 USDA Pesticide Data Program found seven known or probable carcinogenic pesticide residues on potatoes. 10 Blueberries (domestic) were a new addition to the last study, and they made the top 12 again this time. The 2008 USDA Pesticide Data Program found eight known or probable carcinogenic pesticide residues on blueberries. Organic or wild untouched blueberries are better choices. 11 Lettuce did not make the top 12 last year, but it came in at number 11 this time. Given that greens are highly likely to retain pesticides, look for organic when choosing red leaf, green leaf, butter, bibb, romaine, and other types of lettuce. 12 Kale and collard greens share the twelfth spot. A single sample of greens was found to have 66 different pesticides, and a single sample revealed ten. The 2008 USDA Pesticide Data Program found six known or probable carcinogenic pesticide residues on both kale and collard greens.

20 Least Contaminated Foods (beginning with the least) 1 Onions 2 Sweet corn 3 Pineapple 4 Avocadoes 5 Asparagus 6 Sweet peas 7 Mango 8 Eggplant 9 Cantaloupe 10 Kiwi 11 Cabbage 12 Watermelon 13 Sweet potatoes 14 Grapefruit 15 Mushrooms 16 Winter squash 17 Plums (domestic) 18 Cranberries 19 Papaya 20 Tomatoes

See also

Do Pesticides Cause Prostate Cancer?

References

Environmental Working Group, Shopper’s Guide to Pesticides

What On My Food? http://whatsonmyfood.org/index.jsp