Well, the best way to know the details is to visit a parmigiano factory. And the Emilia-Romagna is full of them. Especially the provinces of Parma, Reggio Emilia, the part of Bologna west of Reno, and Modena (all in Emilia-Romagna) as well as the part of Mantua in Lombardy that lies south of the river Po.
EATING IN MODENA
We have eaten, tried and savored more than we had seen in Modena, but that was all part of the plan.