 The grocery chain operates more than 7,700 food stores in the eastern United States plus several European countries. It also operates Hannaford grocery stores. The Harberston Slade building, which houses town offices and the Council on Aging, will be open as a cooling center today and tomorrow. Today the cooling center will be open from 9 a.m. until 7 p.m. and then tomorrow from 9 a.m. to 4 p.m.