"Azodicarbonamide is the same chemical used to make yoga mats, shoe soles, and other rubbery objects," Hari writes. "It's not supposed to be food or even eaten for that matter. And it's definitely not 'fresh.'"
The difficult-to-pronounce chemical is described by the Food and Drug Administration as a "dough conditioner," intended to strengthen dough and improve elasticity (always an important quality in bread). While a 1999 World Health Organization evaluation of the effects of azodicarbonamide found a negligible impact in animal test subjects, a study in which rats and dogs were subjected to biurea, a product of the chemical, resulted in the deaths of several animals. Another product, urethane, is a recognized carcinogen and appears at higher levels in bread.
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"The level of risk is uncertain," WHO told CNN.com. "Hence, exposure levels should be reduced as much as possible." Nevertheless, the use of the chemical in the workplace carries a greater level of exposure. According to the same evaluation, some employees of facilities using or manufacturing azodicarbonamide experienced asthmatic reactions. The concentration needed to induce asthma is unknown.
"We are already in the process of removing azodicarbonamide as part of our bread improvement efforts despite the fact that it is a USDA and FDA-approved ingredient," Subway said in a statement. According to the Associated Press, a Subway representative said a change in policy was underway before Hari's petition was launched, but did not specify when it was started or when it would be complete.
"Subway couldn't force most of us [into their shops] at gunpoint," reads one comment on Hari's blog. But not all readers are convinced of the chemical's toxicity. "There is a misconception that just because a chemical has an industrial use, it is toxic and should not be in food," another reader wrote. "It is not the chemical that is toxic. It is the dose in which you take it."
CNN.com reports that besides Subway, McDonald's, Starbucks, and Arby's also use the chemical, and it can appear in grocery store and restaurant breads. Nevertheless, Hari writes, the ingredient is banned in Europe and Australia, and its use in Singapore can result in a $450,000 fine and up to 15 years in prison.
"I commend Subway for finally responding to me and now over 58,000 concerned citizens," she told USA Today after the announcement that the restaurant would end their use of the chemical. "I'd like to note that current Subway sandwiches still have this ingredient, and I urge everyone not to eat their sandwich bread until they have finally removed the ingredient."
Subway isn't the only fast-food franchise to attract controversy lately. McDonald's drew ire after an employee was allegedly fired for offering food to a homeless person, and a Chicago sub shop was slammed for firing 20 of its employees just days before Christmas.
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Subway to Remove 'Yoga Mat' Chemical from Bread Following Food Blogger's Petition
'Dough conditioner' may induce asthma at high levels
Mack Gelber a Brooklyn-based writer and editor who has covered entertainment for AOL TV, and contributed fiction to Joyland Magazine and the Bushwick Review. He is a graduate of Oberlin College, where he studied creative writing. Twitter: @mackgelber