I was under the impression from what I have read/DOP specification that only rennet was to be used for Parmigiano Reggiano.
Milk coagulation, obtained exclusively by the use of calf rennet, takes place in bell-shaped copper vats; up to two wheels are made for each vat.
Yet, I come across many Parmigiano Reggiano cheeses imported from Italy with the real Reggiano logo and the DOP symbol (e.g. Tre Stelle, Italissima, President's Choice, Compliments, etc.)
Is it just a loophole in the specification and found only in lower-end Parmasen Reggiano?