The disclosure comes as Subway has suffered from an onslaught of bad publicity since a food blogger petitioned the chain to remove the ingredient.
The ingredient, azodicarbonamide, is approved by the Food and Drug Administration for use as a bleaching agent and dough conditioner. It can be found in a wide variety products, including those served at McDonald's and Starbucks and breads sold in supermarkets. But the petition gained attention after it noted the chemical was also used to make yoga mats.
Tony Pace, Subway's chief marketing officer, told the AP in a phone interview that the chain had started phasing the ingredient late last year and that the process should be complete within a week. Subway is privately held and doesn't disclose its sales figures. But it has apparently been feeling pressure from the uproar.
"You see the social media traffic, and people are happy that we're taking it out, but they want to know when we're taking it out," Pace said. "If there are people who have that hesitation, that hesitation is going to be removed."
He repeated that Subway was "happy to invite consumers back in who might've had hesitation."
Subway, which has about 26,600 U.S. locations, had said soon after the petition surfaced in February that it was already in the process of removing the ingredient. At the time, however, the company wouldn't provide details on a timeline, prompting some to say that the chain didn't really have a plan to remove the ingredient.
Pace stressed that the removal wasn't a reaction to the petition and that the changes were already underway. The company also provided a statement saying it had tested the "Azo-free bread" in four markets this past fall.
"We're always trying to improve stuff," Pace said. For instance, he noted that the chain has also reduced sodium levels over the years and removed of high-fructose corn syrup from its bread.
The blogger who created the Subway petition, Vani Hari of FoodBabe.com, has said she targeted Subway because of its image of serving healthy food. Hari has also called on other companies including Chick-fil-A and Kraft to remove ingredients she finds objectionable.
The sentiment is one that has been gaining traction, with more people looking to eat foods they feel are natural and examining labels more carefully. The trend has prompted numerous food makers to adjust their recipes, even as they stand by the safety of their products. Among the companies that have made changes are PepsiCo Inc., which removed a chemical from Gatorade, and ConAgra, which simplified the ingredients in its Healthy Choice frozen meals.