Storing breastmilk

Ceyonia • 22. Married. Mommy of Titan Amari Smith 😌.
What's the general rules for this? & how are you mamas storing your milk so that none ends up getting wasted? I pumped 6 oz. of milk for my 1 week old baby lastnight so my husband could help me with feedings . When he gave him the bottle, baby only drank about 2.5 oz. so the rest pretty much got wasted because I know I can't put it back in the fridge . How should I store it to prevent this from happening again? Definitely don't wanna continue to waste perfectly good breastmilk .