The Grocery Manufacturers Association (GMA) and some growers of genetically modified crops like soybeans and sugar beets are calling on the Senate to again to take up a bill that would make GMO labeling voluntary and prevent states from passing their own labeling laws.

These groups are concerned that food manufacturers would be subject to a variety of state labeling laws if there's no national standard. Vermont's law requiring labeling goes into effect July 1.  

Acknowledging that consumers want information about GMOs in their food, GMA created a "Smart Label" program in which manufacturers place a QR code on their product labels. Consumers would scan these special bar codes with their smartphone while shopping at the supermarket. The barcode would then take them to the company’s website, where they could get information about GMOs and other ingredients in the products.

Several major food companies have already announced a GMO labeling plan, and some have begun labeling their products.

And many consumers and GMO labeling advocates say that QR codes are not the solution.

Not everyone has smartphones needed to scan these codes. In fact, almost three quarters of people over the age of 65, half of those who live in rural areas, and half of those making less than $30,000 a year, don't have smartphones.

In a 2015 survey by research firm The Mellman Group, 88 percent of consumers said they would prefer on-package labeling for genetically engineered food to scanning a QR code. In fact, only 16 percent of consumers said they had ever scanned a QR code for any reason.  

Backers of labeling want a law such as the one proposed by Senator Jeff Merkley that mandates GMO labeling on packages.

“While it’s good news that some major food companies, in response to Vermont’s law that will require GMO labeling as of July 1, have decided to label their products that contain GMOs nationally, it still amounts to a voluntary decision on their part, which means it could be reversed,” Jean Halloran, director of food policy initiatives at Consumers Union, the policy and advocacy arm of Consumer Reports. “We want all food manufacturers to be required to give consumers information on GMOs in their food. And we want all consumers to be able to find it on the package, not to have to scan a bar code and wade through a website to get it.”