The United States is the world's largest market for foods made with genetically altered ingredients. Many popular processed foods - including soy milk, soup and breakfast cereal - are made with soybeans, corn and other biotech crops whose genetic traits have been manipulated, often to make them resistant to insects and pesticides.
Whole Foods said the prevalence of GMOs in the United States, coupled with a lack of labeling requirements, has made it very difficult for retailers to source non-GMO options and for consumers to identify them.
"We are stepping up our support of certified organic agriculture, where GMOs are not allowed, and we are working together with our supplier partners to grow our non-GMO supply chain," Walter Robb, co-chief executive of Whole Foods, said in a statement.
The United States does not require safety testing for genetically modified ingredients before they go to market. The food industry says the products are safe, but critics say there is a not enough independent research to make that determination.
"We're responding to our customers, who have consistently asked us for GMO labeling and we are doing so by focusing on where we have control: in our own stores," Robb said.
The announcement from Whole Foods comes as the U.S. Food and Drug Administration appears to be on the path to approving genetically engineered salmon.
At the same time, consumer groups are working at the state and federal level to require labels on products that contain GMOs.
Dozens of countries already have genetically modified food labeling requirements, with the European Union imposing mandatory labeling in 1997. Since then, genetically modified products and crops have virtually disappeared from those markets.
Whole Foods in 2009 began putting its 365 Everyday Value product line through non-GMO verification. The chain currently sells 3,300 non-GMO Project verified products, such as its organic tofu, and plans to increase that number.
