(CBS) According to a recent CBS News/New York Times poll, 53 percent of Americans say they won't buy food that has been genetically modified. But CBS News investigative correspondent Armen Keteyian reports that it's not that easy to avoid. While most packaged and processed foods do contain genetically modified ingredients, the labels don't have to say so.
Robyn O'Brien teaches her kids to keep a close eye on the labels of the foods they eat.
"In terms of labeling," she says, "they're not always comprehensive and thorough."
What concerns parents like O'Brien is not what's listed, but what is not. Particularly foods made with genetically modified organisms - or GMOs.
"My concern as a mother is, are these kids part of a human trial that I didn't know that I had signed them up for," O'Brien says.
Today, more than 90 percent of the U.S. soybean crop is genetically modified - had its DNA altered to increase production and withstand chemical weed killers like roundup. Nearly three-quarters of all corn planted in the U.S. genetically modified.
Experts say that means if it comes in a can or a box and the label lists soybean oil or corn syrup as ingredients, odds are that it contains GMOs. Overall, 65 percent of all products in your local grocery store have DNA-altered ingredients...not that you'd know it by looking.
"The industry that makes genetically modified foods fought so hard to make sure that it wasn't labeled," nutritionist Marion Nestle tells Keteyian.
Nestle, a former FDA advisor, says this was a fight that boiled down to one basic fear.
"They didn't want it labeled because they were terrified that if it were labeled, nobody would buy it."
Robert Brackett is spokesman for the Grocery Manufacturers of America.
"I think that consumers have that information available to them if they want to look for it," says Brackett, "You can find it on websites. You can go directly to the manufacturer."
When pressed by Keteyian to explain his organization's role in providing information to the consumer, Brackett said, "Well, it's our responsibility to make sure that the foods that are put in the grocery store shelves are safe."
The FDA and bio-tech giants like Monsanto say there's no evidence that GMOs are anything but safe, but food safety advocates ask: how would we know, if the food is not labeled?
"Labeling is the only way that health professionals are going to be able to trace if there is a problem," says Andy Kimbrell from the Center for Food Safety. "For example, if you're a mother and you're giving your child soy formula and that child has a toxic or allergic reaction, the only way you'll know if that's a genetically-engineered soy formula is if it's labeled."
The FDA does not require "disclosure of genetic engineering techniques...on the label," calling GMOs the "substantial equivalent" of conventional crops.
Baloney, says Kimbrell.
"There is nothing - nothing, substantially equivalent from a conventional crop to a GMO crop," he says. "And in every cell of these new GMO foods are bacterias we've never seen in food before: viruses, genetic constructs, antibiotic bugs that they put in there, laboratory contructs that they've put into every cell of these foods."
A new CBS News poll found that 87% of consumers would like GMO ingredients to be labeled, just as they are in Europe, Japan and Australia. Yet the U.S. Congress has never even held a vote on the issue, to give shoppers the opportunity to exercise their most basic right - to make a choice.
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