MONTPELIER

MONTPELIER, Vt. - Concerned moms won't notice much different about the thin plastic containers of organic baby yogurt. But Stonyfield Farm Inc. hopes they do. Responding to health concerns about possible carcinogens in the former polystyrene containers, the organic yogurt company announced Wednesday it has switched to a plastic made from corn — one of the first plant-based containers for the dairy industry and believed to be the first for yogurt. Polyactic acid or PLA, a polymer made from corn, is nothing new. Last April, Frito-Lay came out with a compostable bag for its SunChips, one which it is