Any reason not to add milk to already frozen milk?

[P.J.]

So everywhere I've checked seems to indicate it's a big no-no to add milk on top of already frozen milk.  But why? I often get only very little milk from my pumping sessions, and then cannot pump again until a couple days later (I know I know, if I pumped the same time each day I'd get more....but I don't). So I freeze what I get, say 2.5 oz, then a couple days later add a couple more ounces into that bottle. My baby has then drunk this milk and we all survived.

The only reason I can think of is that if something goes horribly wrong you are better able to tell which milk caused any reaction, etc. Plus I always date these bottles from the first day of pumped milk, and the original milk is never unfrozen until it's time to drink it. Really I can't see why I should stop doing this.

Anyone can convince me this is truly dangerous or stupid?

[jessica_s]

Hmm I can't think of a reason either other than your making your new milk an older date. Really 2.5 oz isn't that bad. I freeze in 2oz's as to not waste it when I unthaw. I can always take out more but ya can't put it back in. 

You usually don't want to put hot/warm things in the freezer but if your allowing the milk to cool you should be good. 

[PatioGardener]

I think the worry is that warm milk will thaw the frozen milk and allow any bad bacteria that may have 'snuck' in there to multiply. That's a 'food rule' more than a 'breastmilk rule', because breastmilk has such great bacteria and antibodies it is really resilient.

I cooled new milk down in the fridge before adding it to frozen milk, which is half way between the two.

[Anna Phor]

I don't think it's dangerous or stupid!! But I always preferred to freeze in small batches (2-3oz) to minimize waste once I defrosted the milk.

[P.J.]

It's a good idea to freeze in small batches so as not to waste, and I've considered it as it often happens DS only drinks a couple oz and I have to throw the rest away. However, DH and MIL have said it is a hassle to wait to thaw it out when he is really hungry...there have been instances of him screaming those entire 10 minutes while it thawed....so I always take it out and pre-thaw it so all they have to do is warm it up when DS is hungry.

But now that I think about it I could do that with just 2 oz and if he's still hungry after those he won't be screamingly so and they could thaw out another batch.

[CookAMH]

I often did that since I also got a little at a time. I usually tried to chill it first, and only add it if what was frozen was a greater quantity than what was not frozen, just to be safe.

[jessica_s]

10 Minutes is a long time to unthaw!! How are they doing it? I laid the bag in the freezer flat at first so it froze in a thin layer, then when you take it out it takes like 2 minutes to unthaw (running under hot water) heat and pour in a bottle tops! 

[P.J.]

Originally Posted by jessica_s 

10 Minutes is a long time to unthaw!! How are they doing it? I laid the bag in the freezer flat at first so it froze in a thin layer, then when you take it out it takes like 2 minutes to unthaw (running under hot water) heat and pour in a bottle tops! 

Ah, that's clever! When it's like 4 oz frozen in a bottle, it takes around 10 mins to thaw in the Philips bottle warmer.