Widespread power outages, icy conditions hobble U.S. food supply Walmart and Publix close some stores, Tyson Foods scales back production and dairy operations dump milk down the drains. By ANNE D'INNOCENZIO and MAE ANDERSONAssociated Press Share A series of winter storms and widespread power outages gripping Texas and other states not used to such extreme low temperatures are creating big challenges in the nation’s food supply networks. Grocery chains like Walmart and Publix have been forced to close some stores either because of lack of power or lack of workers. And at locations that remain open, customers complain of long lines outside and then empty shelves once brimming with water, bread and milk when they get inside. Texas grocery chain H-E-B, for example, closed some stores and is limiting customer purchases of items like brisket and propane tanks.