Here's a video by Mike Kahn that provides you with information that will help to identify GMO, conventional, and organic produce at the grocery store. This is not magic, it can't look inside the food. But it can give you a tool that will help.
Using PLU codes to Identify GMO Foods
Price Look Up codes went into use in 1990 to identify the type of produce being sold in a grocery story. Most grocery stores use scanners or key-in codes to track inventory at checkout. PLU codes (Price Look Up codes) are printed on labels which are affixed to fruits and vegetables. We can also use these codes to help us figure out what's what! Keep in mind that the system has become a widespread standard, but is voluntary for grocers.
Four digit PLU codes are for conventionally-grown food, while the pre-fix 8 is suggested for use on GMO foods, and the pre-fix 9 identifies organic fruits and vegetables.
A Word of Warning
Consumer advocate Jeffrey Smith emphasizes that GMO codes are hypothetical, and that the pre-fix 8 to indicate GE has not caught on with retailers. Also, there are not many GMO produce items approved in the US beyond alfalfa, corn and Hawaiian papaya. So, while it might seem like a nifty tip, Price Look Up numbers are about just that: price. A more important indicator is the certified organic label, an enforceable standard that excludes genetically engineered foods. (source: Organic Authority)
Buy Local First
Whenever possible, please support your local sustainable growers. Not only will you be getting nutritious wholesome food, you'll also be helping your community by keeping your dollars close to home!