It’s sad when one of the biggest ‘super powers’ can’t even export a quintessentially American food to another country because it is too toxic to eat. But apples treated with diphenylamine (DPA), a substance which keeps them from turning brown for months at a time when they are kept in storage, is now a sore spot for importers of American apples.
DPA isn’t harmful all by itself, but it breaks down into carcinogogenic elements. It’s been used since 1962, but was banned in the European Union in 2012 since producers couldn’t answer inquiries about its safety. European food safety regulators wanted more information on it, but none could be summoned. The apple industry simply responded with one study “that detected three unknown chemicals on DPA-treated apples, but it could not determine if any of these chemicals, apparently formed when the DPA broke down, were nitrosamines.”
British scientists, John Barnes and Peter Magee, in 1956, reported that dimethylnitrosamine produced liver tumors in rats, and later went on to test other nitrosamines and N-nitroso compounds. They found that the compounds caused all kinds of problems, including liver cancer, lung cancer, and even botulism.
“Nitrosamines occur commonly because their chemical precursors–amines and nitrosating agents–occur commonly, and the chemical reaction for nitrosamine formation is quite facile. Research on the prevention or reduction of nitrosamine formation has been productive, and most of the items shown in the table contain considerably lower amounts of nitrosamines than they did a few decades ago.”