If the thawed milk
(which will last only about 6 months max in the freezer) has turned, it will thaw
into a very watery state, not like refrigerated milk. After mixing it around with the floaties, it will no longer have the creamy beige color that breastmilk typically has. It will be grey or slightly green. And it will smell like rotten food, not sour like bad milk, although I have heard of it smelling sour as well.