People who avoid gluten should know that foods that are supposed to be naturally gluten-free are often contaminated.
Grains such as oats, millet, and rice don't have this protein. But a new survey found that some of these products had picked up traces of gluten -- probably from being grown or processed near grains that do contain gluten.
According to Reuters:
"[Researchers] analyzed 22 naturally gluten-free grains, seeds, and flours off supermarket shelves, only looking at products that weren't specifically advertised as being gluten-free ... Seven of the 22 products wouldn't pass the FDA's gluten-free test -- and one product, a type of soy flour, had a gluten content of almost 3,000 parts per million".