Italian curd cheese (10)
(Other definitions for mozzarella that I've seen before include "Buffalo milk cheese" , "Dairy product, originally from buffaloes" , "White Italian cheese" .)
'italian curd cheese' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ricotta that I've seen before include "one brought on board?" , "Cheese - Riot Act (anag)" , "cheese, Italian style" , "Italian curd cheese" , "may be served with biscuits" .)