The Food and Drug Administration has at last outlined specific guidelines for foods that bear the "gluten-free" label.

Kicking in Aug. 5, the rule is that packaged foods will be considered gluten-free if they come under 20 parts of the gluten protein per million, which is the smallest amount that can be measured with accuracy, Bloomberg Businessweek reported.

The FDA has said that around 95 percent of foods that are labeled gluten-free already comply with the guidelines.

"This standard 'gluten-free' definition will eliminate uncertainty about how food producers label their products and will assure people with celiac disease that foods labeled 'gluten-free' meet a clear standard established and enforced by FDA," Felicia Billingslea, the Food and Drug Administration's deputy commissioner for foods and veterinary medicine, said in a statement quoted by USA TODAY.

The 20 parts per million measure is a level that can be safely tolerated by those who have celiac disease, an autoimmune condition where gluten destroys the inside of the small intestine. The protein is found in wheat, rye and barley as well as many prepackaged foods, certain types of alcohol and even vitamins and prescription drugs.

While only around 3 million Americans, or less than 1 percent of the population, actually have celiac disease, the market for gluten-free foods has reached more than $4 billion and is predicted to exceed $6.6 billion by 2017.

A surprising 11 percent of American households say they stick to a gluten-free diet, but just a quarter of them actually cut out grains because of celiac disease, USA TODAY reported.

See Now: OnePlus 6: How Different Will It Be From OnePlus 5?