ATHENS, Greece -- For most Americans, feta cheese is little more than a gourmet after-thought to be sprinkled on salads and burgers. But it's serious business in Greece. So serious that the Agriculture Minister there is forming a "feta police" unit. Never mind that cheese is made from sour milk -- it's one of the country's top exports. And agents will sniff out any problems before it's sent to restaurants and stores around the world. The cheese-control-squad was created following the discovery that thousands of pounds of cheese that was sent to Norway was tainted with listeria. The bacteria can...