The U.S. EPA moved yesterday to revoke approval for a variety of genetically modified corn that has illegally made its way into two brands of taco shells, prompting nationwide recalls. The Starlink corn, manufactured by Aventis, had been licensed for use as livestock feed but banned from human food because of concerns that it could trigger allergies or prove difficult to digest. The EPA decision marks the first time a biotechnology crop license has ever been rescinded. The presence of the Starlink corn in the taco shells was uncovered by the Genetically Engineered Food Alert, a coalition of enviro and consumer groups calling for stricter regulation of biotechnology, and the coalition has suggested that the corn may be found in other food products. At a press conference yesterday, the GE Food Alert criticized the feds and Kraft, maker of one of the contaminated brands of taco shells, because the shells are still being sold in grocery stores nearly three weeks after a recall was announced.