You can thank a chemical called diphenylamine, or DPA, for that. Apples are picked once a year, in the fall, and placed into cold storage until the next harvest, and DPA is sprayed on those apples to prevent black spots known as "storage scald" that can render apples unsaleable. The chemical is regulated as a pesticide, although it doesn't actually kill pests.
And though it's banned in the European Union for use on E.U.-grown apples and pears and strictly regulated on imports, the nonprofit Environmental Working Group (EWG) has just found that the levels on U.S. apples are so high, they're not legally supposed to be sold in the E.U.
The group came upon the discovery during their annual analysis of pesticide levels on produce, in which they scrutinize U.S. Department of Agriculture (USDA) data to determine which fruits and vegetables harbor levels of what harmful pesticides. For the fourth year, apples were dubbed the most contaminated produce, because of DPA and because raw apple samples consistently have five or more pesticide residues. In the most recent USDA data EWG used, DPA was detected on 80 percent of apples at an average concentration of 0.43 parts per million (ppm), well below the U.S. legal limit of 10 ppm. The E.U., on the other hand, has determined that imports should have no more than 0.1 ppm.
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Based on EWG's investigation into the chemical, the World Health Organization and the U.S. Environmental Protection Agency (EPA) are convinced that long-term exposure to DPA isn't harmful, but the E.U. says that conclusion is based on incomplete and inadequate safety data compiled by the produce industry. Food safety officials there point to evidence that DPA can be contaminated with carcinogenic nitrosamines, which have been linked to stomach and esophageal cancers. Despite pressing the industry for more conclusive data that DPA doesn't form nitrosamines when applied to apples, the industry provided them with a single study. So the European Food Safety Authority, taking the precautionary approach, set its limit of 0.1 ppm in March 2014 (setting the level to zero would be unrealistic because DPA can contaminate untreated apples stored along with treated apples).
EWG is now asking the EPA to investigate DPA for the first time since 1998 and determine whether it should still be approved for use. " As science has advanced, researchers have discovered that pesticides once thought safe are, in fact, toxic," Ken Cook, EWG's president, wrote. "The American public deserves the same level of protection as Europeans from pesticide risks. We urge EPA to halt the use of DPA on U.S. fruit until a rigorous analysis … can prove that it poses a reasonable certainty of no harm to consumers."
"We know from the EWG's Dirty Dozen list that there have been several reasons established to choose organic apples. If you buy only one item organic, make it apples," says 'Coach' Mark Smallwood, executive director of Rodale Institute, the nation's oldest organic farming research organization. There are methods that some organic farmers use that prevent scald, mainly through controlling oxygen levels in storage areas and keeping the apples at near-freezing temperatures, that don't require risky chemical treatments.
But also, small organic farmers recognized the value of seasonality: To get the most out of their crops, many turn their harvest into apple ciders, butters, and sauces rather than wasting money and energy on long-term storage. "What we do is harvest our apples, sell as much of the crop as possible right away, store some fruit for wholesale in cold storage with the goal of marketing it in two months, then sell the rest as processing fruit," says Jeff Moyer, farm director at Rodale Institute, which pioneered the science of growing organic apples on the East Coast, where the climate isn't condusive to organic tree fruits. "We cannot market fresh fruit year-round under our system."