Parmigiano Reggiano DOP is still produced as it was in the 13th century. Preservatives and additives are still not used today and the area of production has stayed the same over the centuries: the provinces of Modena, Reggio Emilia, Parma and part of Bologna and Mantova. The Consortium for the Protection of Parmigiano Reggiano guarantees that the strict standards of identity of production are respected and promoted around the world. After twelve months, which is the minimum time required for aging, some experts from the Consortium examine every single wheel and only the ones that respect the strict requisites can be heat branded.