So; we’ve talked about pumping your milk. Now you need to know how to store it safely so your baby can drink it later.
How Long Can I Store It For?
Firstly, you will need to know how cold your refrigerator is. If it doesn’t have a built in thermometer, it’s best to buy one so you can adjust the temperature if necessary.
Expressed breast milk can be stored for:
- 72 hours in the fridge, as long as it’s at 4 degrees C or lower
- 2 weeks in the freezer compartment of a fridge (due to continuous opening and closing of the door, it can’t be stored for longer than this)
- 3-4 months in the coldest part of your freezer (if your freezer has a separate door to the fridge)
- 6 months in deep freeze at a continuous temperature of -18 degrees C
It is best to store your milk in the fridge if at all possible. Freezing breast milk does kill off some of the antibodies, and because your breast milk changes over time to suit your baby, it is best to use any milk you pump as soon as possible. However, frozen milk from 6 months ago is still much better nutritionally for your baby than formula milk.
If you are going to freeze your milk, it should be frozen immediately after pumping.
If you struggle to pump more than an ounce or two at each pumping session, you can actually add to the same ‘pot’ of breast milk throughout the day. However, this should only be done over the period of a day and the milk should be used within 72 hours of the first pumping session.
What Can I Store It In?
Human milk can be stored in plastic or glass feeding bottles with sealing discs instead of teats, in special bags designed for the storage of breast milk, or indeed in any hard-sided glass or plastic bottle. Make sure that you clearly label the bag or container with the time and date of pumping (and your name, if you are storing the milk in a public fridge!).
How Do I Prepare It?
We must take more care of human milk than we do of formula milk. Human milk is a live substance, and treating it ‘roughly’ can diminish the nutritional properties (although I can guarantee that it would still be better than formula!).
To thaw frozen breast milk, it is best to let it defrost in the fridge. Once defrosted, it will be okay unopened in the fridge for up to 24 hours. However, if time is of the essence, it’s okay to let it thaw at room temperature. Just make sure it is used within 4 hours of thawing. If you need to heat it for your baby, run the bottle or container under a warm running tap, or place in a jug of warm water. Microwaves should NOT be used and the milk shouldn’t be brought to boiling point. However, if you find your milk has a rancid smell after freezing, it may be that it is particularly high in Lipase. In this case, it is useful to ‘scald’ the milk prior to freezing by bringing it to boiling point.
It is perfectly normal for human milk to separate, with the ‘cream’ floating on the top. To mix it together, swirl the container gently or stir with a sterile spoon. Try to avoid vigorous shaking of the milk if you can.
What About Leftovers?
There seems to be quite a lot of conflicting advice on what to do with leftover milk. However, the ‘rules’ for safe use of formula milk state that the milk should be discarded once the baby has finished, and not saved for later. It seems to make sense to treat human milk in the same way.
Can I Mix It With Formula?
If supplementation is necessary, it is fine to mix human milk with formula milk. However, it is better to give the human milk first and then ‘top up’ with the formula afterwards. This is so that the baby definitely receives all of the breast milk, and just takes what formula they need to fill the gap.
Remember that lots of different sources offer different advice on the safe storage of breast milk. If you are in any doubt, talk to your healthcare provider or somebody from La Leche League for up-to-date information.