What is the white substance floating in my fresh mozzarella brine? I purchased fresh mozzarella bocconcini from Whole Foods six days ago. The mozzarella is sold in a brine solution. I opened the package when I bought it and have kept it refrigerated since, using the original packaging and brine solution. Today, I opened the package again to see some white substance floating in the brine as shown below. The mozzarella smells fine, and based on eating one bite, also tastes normal.



What is this substance, and is my mozzarella still safe to eat?
Those are just milk solids.

Quality mozzarella is sold floating in whey, the leftover liquid from making cheese.  While most of the milk solids are gone from the whey -- that's what the cheese is made from -- not all of them are.  As such, some will coagulate in the fridge, floating on top of the whey.

Now, if the floaters were any color other than white, or if they were fuzzy, that would mean mold.  But those are really just cheese bits.