"Ultimately, it is the food producer who is responsible for assuring safety," the FDA wrote in a statement to the Tribune, noting that manufacturers are encouraged to consult with the agency about their products.
"Until there's federal government mandated labeling of GMO ingredients, there's no way to tell if packaged products contain GMO ingredients," Dickson said. "Our approach is to work in the spirit of partnership with our suppliers … to encourage them to take active steps to avoid GMO ingredients."
Basu notes that GMO crops have been embraced by farmers in many countries — although not in Japan, Europe or Britain — and cites an International Food Information Council study that found 68 percent of those surveyed believe that FDA's current labeling practices are sufficient.
"If you look at the adoption of biotech by over 24 countries and over 2 billion acres of biotech crops globally that have been grown in the last 15 years of commercialization, consumers are buying these products," he said.
Still, Nielsen announced last year that "non-GMO" was the fastest-growing health and wellness claim on store-brand foods in 2009, up by 67 percent from the previous year and representing $60.2 million in sales.
And 2010 brought a new "Non-GMO Project Verified" seal, offering third-party certification that less than 0.9 percent of the ingredients in the product came from genetically modified organisms. More than 4,000 products — including all Whole Foods store brands — have been enrolled in the program, according to executive director Megan Westgate.
Shoppers at Whole Foods last week were conflicted about whether the store should be selling genetically modified foods. But the majority said they were surprised to find it did.
"It's disappointing and disheartening. I feel like Whole Foods has established itself as a community for people who believe in healthy food and I feel like they embody that. So I would think that they would uphold standards and prevent foods like this from being sold here," said Melissa Hayes, of Chicago.
"But I don't think it's fair to just blame Whole Foods," she added. "I think it's equally important for the consumer to take an active role and find out information on GMOs and Monsanto. Every time you make a purchase it's a vote and people just need to be more conscious and aware."
If you want to avoid GMOs
Several shopping guides have been published in recent years offering vetted lists of products that do or don't contain biotech ingredients. They include the Non-GMO Shopping Guide, the Greenpeace Shoppers Guide and an iPhone app from the Non-GMO Project.
They also offer general guidance on avoiding GMO foods, including:
•Look for the Non-GMO Project Verified seal, which is the only third-party-tested verification program in the U.S.
•Choose certified organic foods, which cannot contain genetically modified ingredients or feed (for animals) as part of their certification.
•The most common genetically modified crops are field corn (used for grain, processed food ingredients and animal feed), soy, canola, cotton, alfalfa, sugar beets, wheat, rice and flax, although the last three are not yet commercially grown.
•These crops often are added to processed foods as oils, sweeteners and soy proteins but also can be part of amino acids, aspartame, ascorbic acid, sodium ascorbate, vitamin C, citric acid, sodium citrate, ethanol, flavorings (natural and artificial), hydrolyzed vegetable protein, lactic acid, maltodextrins, microbial growth media, molasses, monosodium glutamate, sucrose, textured vegetable protein, xantham gum, vitamins and yeast products, according to the Non-GMO Project.
•Unless sugar is labeled as pure cane or organic, it likely contains sugar from genetically modified sugar beets.
•Most fresh produce is GMO-free except Hawaiian papaya, crookneck squash, zucchini and a small percentage of sweet corn.
Whole Foods and Trader Joe's say all their store brand items are sourced from non-GMO foods.