The Food and Drug Administration on Friday finalized its definition of what it takes for food to qualify as "gluten-free."
The official government designation came nine years after Congress asked the agency to establish a standard for companies wanting to label their products as gluten-free.
In the interim, a growing number of manufacturers have leaped into the lucrative and exploding market for foods without gluten, a protein found in barley, wheat and rye. While several independent groups certify products as gluten-free, until Friday there was no government standard for what it takes to earn that label.
About 1 in 133 Americans suffer from celiac disease, an autoimmune condition in which consuming gluten can damage the lining of the small intestine and contribute to a range of health issues.
The new rule says that in order for a product to be marketed as "gluten-free," it must contain less than 20 parts per million of gluten.