Think Philadelphia, and you think freedom; fly, Eagles, fly; Fresh Air with Terry Gross; and, of course, Philly cheesesteaks - sliced beef and melted cheese on a hoagie roll or, should I say, hoagie.

Philadelphia is known as the city of brotherly love. But that love can be tested when it comes to sports rivalries - also when it comes to the ingredients that make a cheese steak great. Recently, the ...