FDA Adopts Labeling Rules for Gluten
The Food and Drug Administration has issued final rules about using "gluten-free" and similar terms on food labels. Foods claiming to be "gluten-free," "free of gluten," and “without gluten," or to have "no gluten," must have fewer than 20 parts per million of gluten, a protein found in wheat, barley, and rye. Studies suggest that this level is safe for some people with celiac disease, who must avoid gluten. In addition, current analytical methods can't reliably detect gluten at levels lower than this threshold.
Source: Federal Register, Aug. 5, 2013