Gimp_of_01 buys regular Wisconsin cheese out of the "ends and pieces" bin at his local store.  These are vacuum sealed.  I have also bought those 1/2 lb bricks from Kraft.  These are hermetically sealed also.

Block cheeses such as these last quite a while, many weeks at least.  They do get soft but still are good.  I'd say that shredded cheeses would congeal into a goo-ball within a short period due to pressure and temperature.