Can you combined cold milks?
Yes just make due both milks are cold separately first and then you can mix it.
I do this all the time since I usually don't get enough extra from one day to freeze. As long as the new milk is cold before adding it, it's fine. Just make sure when you date it, it's dated to the earliest date of milk in the mix (mixed Mon, Tues, and Weds, label mix as Mon). I usually try not to mix more than 2-3 days worth that way I'm not dating it back too long, and the milk is as fresh as possible when freezing.
Thank you ladies, this has cleared up my confusion.
I think you can if both milk is cold before you combine. Can't add fresh milk to cold milk.*