DrPizza
Administrator Elite Member Goat Whisperer
Of commercial mozzarella I've not noticed any real difference between Polly-o, Sargento, Calabro, Sorrento and store brands. I doubt anyone but a cheese expert could tell one from the others blindfolded.
One thing is that in any brand there's a BIG difference between the full fat version and the part skim version. The part skim always melts funny and browns badly, I won't go near the stuff anymore.
There seems to be some variation, even within the same brand, from month to month. It's only minor, but sometimes, the blocks of cheese are a little softer. And, occasionally, you'll get a block with a couple little bubbles of liquid in them. So, with that variation - no, I don't think most people could tell the difference, though some brands come in consistently firmer blocks. I preferred the firmer, drier stuff - it was easier to grind, and easier to clean the grinder after doing a few hundred pounds.