It's true that behind the glass door you'll find food, but not a lot. In order to find the cache look at the following statements and find he ones that truly describe food that you might find behind the glass door.
Behind the glass door you'll find butter but no bread: N48 29.529
Behind the glass door you'll find bacon but no eggs: N48 29.906
Behind the glass door you'll find cherries but no apples: N48 28.987
Behind the glass door you'll find tea but no coffee: W089 11.822
Behind the glass door you'll find cherrios but no shreddies: W089 11.537
Behind the glass door you'll find beef but no pork: W089 11.280