Apples Doused with Chemical After Harvest

TUESDAY, APRIL 10, 2018

Apples are generally near the top of EWG’s Dirty Dozen™ list because they contain an average of 4.4 pesticide residues, including some at high concentrations. One chemical found on apples in particular has triggered an intense international debate, set U.S. and Europe on radically different courses, and given Americans one more reason to buy organic apples.

Few Americans may realize, but most conventionally grown apples are drenched in diphenylamine, an antioxidant chemical treatment to prevent the skins of apples in cold storage from developing brown or black patches known as “storage scald.” Tests of raw apples conducted by U.S. Department of Agriculture scientists in 2016, the most recent year for which data are available, found diphenylamine on 80 percent of them, with an average concentration of 0.28 parts per million.1

American apple growers contend that diphenylamine is a benign treatment. European officials, on the other hand, are not satisfied that the chemical may be harmless. Beginning in 2014 it enacted a restriction on any imported apples and pears treated with the chemical.2 The USDA reports that apple exports from the U.S. to Europe declined by two-thirds since this restriction took effect.3

Since diphenylamine is sprayed on fruit after it is harvested, USDA tests of apples find it more often and at greater concentrations than most other pesticide residues. (Diphenylamine is regulated as a pesticide, but it does not kill insects, weeds or fungal growth.) Diphenylamine was also found in 36 percent of applesauce samples, but at much lower concentrations.

The U.S. Environmental Protection Agency reviewed the safety of diphenylamine in 1998 and concluded that its use posed no unacceptable risk to people or the environment.4 It is scheduled to update its safety assessment in 2018, but presently allows maximum concentrations of diphenylamine of 10 parts per million on apples and 5 parts per million on pears.

European regulators, to the contrary, ascribe the absence of evidence of harm to poor investigation. They concluded that the manufacturers of diphenylamine had not provided enough testing to prove that their product and any chemicals formed when it broke down were safe.5

The European officials concerns center around the possible formation of nitrosamines on diphenylamine-treated fruit. Nitrosamines cause cancer in laboratory animals, and some studies have found that people who eat foods with nitrosamines have elevated rates of stomach and esophageal cancers.6 Nitrosamines form when nitrogen-containing compounds combine with amines, like diphenylamine. Since the 1970s, government agencies have regulated foods and consumer products to limit concentrations of chemicals that can serve as building blocks of nitrosamines.

Since Americans eat on average nearly 10 pounds of raw apples every year,7 even low levels of nitrosamines on apples could potentially pose a risk to human health.

European regulators theorized that nitrosamines could be generated if diphenylamine combined – either during storage or when fruit was processed – with a source of nitrogen, an element ubiquitous in the environment. But they had little hard evidence that this chemical reaction was, in fact, occurring. Beginning in 2008, they pressed the chemical companies that make diphenylamine for test data that showed whether nitrosamines or other harmful chemicals formed when containers of diphenylamine sat on shelves, when fruit was treated with diphenylamine and stored for a long time, and when diphenylamine-treated fruit was processed into juices, purees and sauces.8 The industry provided one study that detected three unknown chemicals on diphenylamine-treated apples at concentrations greater than 50 parts per billion, but it could not determine if any of these chemicals were nitrosamines. It did not study whether nitrosamines were being formed on diphenylamine-treated apples made into apple juice or applesauce.

In 2012 the European Food Safety Authority, a government body that evaluates the risk of pesticides for the European Commission, concluded that the industry had not provided sufficient information and that the many data gaps made it impossible to confirm the safety of diphenylamine. The full Commission reduced the allowable level of diphenylamine on imports to 0.1 part per million.9 It did not set the permissible level of diphenylamine at zero because untreated apples can sometimes acquire traces of diphenylamine when warehoused in storage facilities that have also held diphenylamine-coated apples. American growers who export apples and pears to Europe use special diphenylamine-free warehouses to avoid cross-contamination. Europe’s temporary residue level of 0.1 part per million is set to expire in 2018.

The U.S. EPA has taken few steps to respond to the European ban or the concerns about nitrosamines expressed by European food safety officials. Its website states that a reregistration review is underway with a draft risk assessment scheduled for release during the first quarter of 2018.

Until the latest scientific techniques can determine the safety of diphenylamine, people can reduce their risk of ingesting nitrosamines and other potentially dangerous pesticide residues by eating organic apples, apple juice, applesauce and pears.



  1. USDA, Pesticide Data Program: Annual Summary, Calendar Year 2016. U.S. Department of Agriculture, February 2018.
  2. European Commission, European Commission Regulation No 772/2012, 8 August 2013, Amending Annexes II, III and V to Regulation (EC) No 396/2005 of the European Parliament and of the Council as Regards Maximum Residue Levels for Diphenylamine in or on Certain Products. Official Journal of the European Union, 2013, L 217/2. Available at eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2013:217:0001:0027:EN:PDF
  3. USDA Foreign Agricultural Service, EU-28 Fresh Deciduous Fruit Annual 2017. GAIN Report number: AU1709, U.S. Department of Agriculture, 2017. Available at gain.fas.usda.gov/Recent%20GAIN%20Publications/Fresh%20Deciduous%20Fruit%20Annual_Vienna_EU-28_10-24-2017.pdf
  4. EPA, Reregistration Eligibility Decision (RED) Diphenylamine. EPA738-R-97-010. Environmental Protection Agency, April 1998. Available at https://archive.epa.gov/pesticides/reregistration/web/pdf/2210red.pdf
  5. European Food Safety Authority, Conclusion on the Peer Review of the Pesticide Risk Assessment of the Active Substance Diphenylamine. EFSA Journal, 2012, 10(1):2486-2527.
  6. National Toxicology Program, N-nitrosamines. Report on Carcinogens, Fourteenth Edition, 2016. Available at ntp.niehs.nih.gov/ntp/roc/content/profiles/nitrosamines.pdf
  7. USDA, Bananas and Apples Remain America’s Favorite Fresh Fruits. U.S. Department of Agriculture, August 27, 2012. Available at www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=76020
  8. European Food Safety Authority, Conclusion Regarding the Peer Review of the Pesticide Risk Assessment of the Active Substance Diphenylamine. EFSA Scientific Report, 2008, 188.
  9. European Commission, European Commission Regulation No 772/2012, 8 August 2013, Amending Annexes II, III and V to Regulation (EC) No 396/2005 of the European Parliament and of the Council as Regards Maximum Residue Levels for Diphenylamine in or on Certain Products. Official Journal of the European Union, 2013, L 217/2. Available at eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2013:217:0001:0027:EN:PDF

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