Parmesan is an Italian hard, granular cheese produced from cow's milk and aged at least 12 months or, outside the European Union and Lisbon Agreement countries, a locally produced imitation. It has been called the "king of cheeses" and "practically perfect food". Parmigiano Reggiano is made from unpasteurized cow's milk. The whole milk of the morning milking is mixed with the naturally skimmed milk of the previous evening's milking, resulting in a part skim mixture.

Source: Wikipedia