The FDA released the long-awaited proposed rule on gluten free labeling. The text of the proposal is published in the Federal Register.  A prospective double-blinded, placebo-controlled trial conducted by the University of Maryland Center for Celiac Research played a major role in establishing the proposed standard. The study established a safe gluten threshold for patients with celiac disease. 

In very brief summary, the FDA is proposing to set a standard of 20 part per million as the acceptable level of gluten allowed for a product to be labeled as 'gluten-free.'

SUMMARY: The Food and Drug Administration (FDA) is proposing to define the term "gluten-free" for voluntary use in the labeling of foods, to mean that the food does not contain any of the following: An ingredient that is any species of the grains wheat,  rye, barley, or a crossbred hybrid of these grains (all noted grains are collectively referred to as "prohibited grains");an ingredient that is derived from a prohibited grain and that has not been processed to remove gluten (e.g., wheat flour); an ingredient that is derived from a prohibited grain and that has been processed to remove gluten (e .g., wheat starch), if the use of that ingredient results in the presence of 20 parts per million (ppm) or more gluten in the food; or 2O ppm or more gluten. A food that bears the claim "gluten-free" or similar claim in its labeling and fails to meet the conditions specified in the proposed definition of "gluten-free" would be deemed misbranded. FDA also is proposing to deem misbranded a food bearing a gluten-free claim in its labeling if the food is inherently free of gluten and if the claim does not refer to all foods of that same type (e.g., "milk, a glutenfree food" or "all milk is gluten-free") . In addition, a food made from oats that bears a gluten-free claim in its labeling would be deemed misbranded if the claim suggests that all such foods are gluten-free or if 20 ppm or more gluten is present in the food.