The True Food Network is the [CFS] Center For Food Safety’s grassroots action network where concerned citizens can voice their opinions about critical food safety issues, and advocate for a socially just, democratic and sustainable food system.
Here is a pdf that provides guidelines for buying non-GMO foods in your local stores.
SPECIAL NOTE [from CFS]: This guide was compiled based on company statements, not genetic testing. Any product labeled as Non- GMO indicates that its manufacturing process is designed to avoid GMOs, but consumers should be aware that GM contamination is possible due to natural pollen movement, weather events, seed contamination, or human error. Hence there is no guarantee such products are 100% free of GMOs.
You can download the guide here.