Gluten-Free Foods List - EatingWell www.eatingwell.com/article/288100/gluten-free-foods-listPrivate View Currently, using a "gluten-free" label is optional on food products sold in the U.S. All products that are labeled "gluten-free" must contain less than 20 parts per million (ppm) gluten.The 20 ppm threshold was set because it is virtually impossible to reliably detect levels below this (it's like finding a grain of sand in a swimming pool).