BOULDER — You'll know whether the food you're eating was grown with genetically modified seeds if a GMO labeling bill sponsored by U.S. Rep. Jared Polis is approved by Congress.

Polis, D-Colo., announced the genetically modified organism, or GMO, labeling bill at a press conference at Alfalfa's Market in Boulder on Wednesday. Rep. Peter DeFazio, D-Ore., and Sen. Barbara Boxer, D-Calif., are co-sponsoring the bill.

More than 50 nations already require labeling of genetically modified foods. Locally, Alfalfa's Market – led by its chairman, Mark Retzloff – took the lead in the GMO-Free Boulder advocacy group in 2011.

Members of the group mounted a campaign to ban all genetically modified crops from open-space land owned by Boulder County and leased to farmers. Boulder County commissioners voted to allow some genetically modified foods on the land, but also offer economic incentives to farmers who transition to organic crops.

A new, federal GMO labeling law would be good for business and for Colorado farmers, Polis has said. One potential benefit if the law passes, he said, is that American crops would be ready for export to other countries that require GMO labeling.

Opposition to GMO labeling has been fierce in other parts of the nation. For example, a labeling bill in California was defeated in November after Dupont (NYSE: DD), Monsanto Co. (NYSE: MON) and Pepsi Co. Inc. (NYSE: PEP) spent an estimated $46 million on TV ads against it, according to published reports.