Following Subway's announcement, McDonald's spokeswoman Lisa McComb told CNBC: "Azodicarbonamide is commonly used throughout the baked goods industry, and this includes some of the bread goods on our menu. While this ingredient is recognized as safe and approved by the FDA, we listen to our customers and evolve to continue to serve the great tasting, quality food they expect from McDonald's. This ingredient, like all the ingredients we use, is available to consumers on our website."
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In an email to CNBC, Dunkin' Donuts said, "There are trace amounts of azodicarbonamide, a common ingredient approved as safe by the Food and Drug Administration, in three Dunkin' Donuts bakery items, including the Danish, Croissant and Texas Toast. All of our products comply with federal, state and local food safety standards and regulations. We are evaluating the use of the ingredient as a dough conditioner in our products and currently discussing the matter with our suppliers."
Following Hari's petition, the nonprofit Center for Science in the Public Interest lobbied for the USDA to consider barring it. It noted that when bread containing the chemical is baked, it produces the carcinogen urethane and "leads to slightly increased levels of urethane in bread that pose a small risk to humans" when azodicarbonamide is used at its maximum limit.
Evidence also suggests the product is harmful in its more industrial form. The United Kingdom's Health and Safety Executive lists it as a substance that can cause occupational asthma.
Meanwhile, a World Health Organization report states, "Case reports and epidemiological studies in humans have produced abundant evidence that azodicarbonamide can induce asthma, other respiratory symptoms, and skin sensitization in exposed workers. Adverse effects on other systems have not been studied."