A standard definition for gluten-free foods is being finalized by the U.S. Food and Drug Administration. It\'s expected that foods claiming to be gluten free would be required to have no more than 20 parts per million gluten, which is the European standard, ABC News reported. The purpose of the standard is to protect the 1.5 million to 3 million Americans with celiac disease, a genetic disorder that causes an intolerance to gluten, a protein found in grains such as wheat, rye and barley. It\'s also found in many processed foods, soups, sauces and salad dressings. In the U.S., sales of food products labeled as \"\"gluten-free\"\" totalled nearly $3 billion a year,ABC News reported.