Would Parmesan by any other name be as tasty atop your pasta? A ripening trade battle might put that to the test. As part of trade talks, the European Union wants to ban the use of European names like Parmesan, feta and Gruyère on cheese made in the United States. The argument is that the American-made cheeses are shadows of the original European varieties and cut into sales and identity of the European cheeses. The Europeans say Parmesan should only come from Parma, Italy, not those familiar green cylinders that American companies sell. Feta should only be from Greece, even...