Mainstream GF products can change formulations at any time, without notice. If you choose a mainstream grocery item because you saw it on a GF list, recheck the ingredients. The lists below were made by the company, and are as current as was possible to obtain. Some lists update themselves automatically, some do not. First thing you should do is check for a date.
Glutenista.com Gluten Free Product Lists for both Certified Gluten Free and Mainstream Gluten Free