Storing and Handling Breastmilk Part 2

When nursing, it is easy, no worries about is the milk fresh, does it need to be warmed or what to do if she doesn’t finish the bottle.  When parents begin giving a bottle of expressed breastmilk many questions arise that they had never thought about before.  Part two of this blog is about safely handling breastmilk.

handling breastmilk

A common myth I hear when handling breastmilk is that you cannot add fresh breastmilk to previously refrigerated or frozen breastmilk or combine breastmilk from different pumping sessions. Yes, you can combine fresh room temperature expressed milk from your current pumping session to a batch in the refrigerator that is already cold.  You can also add freshly expressed milk to frozen breastmilk as long as it is less than the frozen amount but in this case it must be cooled for about an hour so it doesn’t melt the frozen milk.  When adding fresh expressed milk to an older batch you must label the date at the older batch date.

There are several ways to thaw frozen breastmilk. Your options include

  1. Thawing it in the refrigerator overnight.
  2. Running the container under cool to warm running water till thawed.
  3. Placing the container in a pan of previously heated water that has been removed from the stove.  Do not leave pan on stove that is actively heating the water while container of milk is in it.

Whatever method you use make sure when thawing no water seeps into the container diluting the breastmilk.

I highly recommend warming your breastmilk to body temperature when feeding newborns and young babies. Cold milk can lower their body temperature.  For older babies, cold milk is okay if they will accept it.  Never use a microwave to thaw or warm your babies milk.  It will destroy your milk’s anti-infective factors and it is dangerous because it can create hot spots due to uneven heating and burn your baby’s throat.

So what do you do when your baby does not finish her bottle and you have breastmilk still left in the bottle?  When handling breastmilk most recommendations are to throw out the milk because it is believed that when the baby’s saliva mixes with the milk it creates harmful bacteria if not consumed quickly. There are no scientifically published studies on this topic but some unpublished ones.  La Leche League has gone on record to say that the leftover breastmilk can be used at the next feeding only and should be used alone and not added to more breastmilk.  They consider it safe. This is a grey area so I would encourage you to make up your own mind and do what fits your situation the best.

Finally, I would like to share a link with you when traveling with breastmilk through airport security.  You are permitted to bring breastmilk through security in quantities greater than 3 ounces with traveling with your baby or without your baby.  Please go to  for more information.

Please remember all they guidelines are for breastmilk and for healthy full term babies.  Other circumstances could differ.

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