A massive legal loophole means companies can add new ingredients to foods with no government safety review.

Rebecca Fattell was enjoying breakfast at a hotel in Berlin last summer when, after a few bites of a roll, her mouth started to itch, her gums started to hurt and before long, hives covered her skin.

“My face, trunk, arms, legs,” Fattell said, “they were all beet red.”

She rushed to the emergency room.

Fattell, who is allergic to peanuts, is vigilant about what she eats and had been assured by hotel staff that her breakfast didn’t contain any. Hidden in the pastry, however, was lupin flour, which is made from a peanut-related legume that caused her reaction.

“I’m extremely careful,” said the 23-year-old New Yorker. “I just had no idea about lupin.”

Lupin is considered a “major food allergen” in Europe and must be labeled accordingly on packaged foods. In the United States, where lupin is less commonly used, there is no such requirement, leaving Fattell and others who suffer from peanut allergies vulnerable.

The U.S. Food and Drug Administration has known about lupin’s effects since at least 2008, but has made no move to require companies to identify it as an allergen on products sold in the United States.

Lupin is just one of thousands of ingredients companies have added to foods with little to no oversight from the FDA. They’ve taken advantage of a loophole in a decades-old law that allows them to deem an additive to be “generally recognized as safe” — or GRAS — without the agency’s blessing, or even its knowledge.

The loophole is so big that companies can market additives, like lupin, that the FDA has found to pose dangers. Even ingredients the agency has agreed are GRAS are now drawing scrutiny from scientists and consumer groups who dispute their safety.

Critics of the system say the biggest concern, however, is that companies regularly introduce new additives without ever informing the FDA. That means people are consuming foods with added flavors, preservatives and other ingredients that are not at all reviewed by regulators for immediate dangers or long-term health effects.

People are consuming foods with added flavors, preservatives and other ingredients that are not at all reviewed by regulators for immediate dangers or long-term health effects.