Parmesan cheese does go bad, but it can outlast the printed expiration date, according to EatByDate. Parmesan cheese kept in the refrigerator is usually good two to four months past the expiration date. When kept in the freezer, it is good for six to eight months after the expiration date.
The shelf life of parmesan cheese is so good because it is a hard cheese, and hard cheeses tend to keep fresh longer. According to Eat by Date, even once mold begins to grow on a small area of the cheese, it is still okay to eat. Simply cut away the moldy area and continue eating.