Freshly expressed breast milk
According to the Australian Breastfeeding Association, freshly expressed breast milk shouldn't be stored in the fridge any longer than 72 hours.
They also recommend that you store it towards the back of your fridge where the temperature is coolest.
With regards to the equipment you use: "If you are expressing several times a day for a healthy baby, your expressing equipment should be rinsed well in cold water after each use to remove the milk."
Storing breast milk in the fridge
In contrast, the Mayo Clinic says fresh breast milk can be stored in the fridge for up to 5 days and can be left at room temperature for up to 6 hours although the optimal time is 4 hours.
They advise you to "store the expressed milk in a clean, capped glass or hard plastic, BPA-free container." And add; "If you're storing expressed milk at your baby's child care facility, add your baby's name to the label."
But what about leftover breast milk? Parents.com suggest you can refrigerate it then offer it at the next meal but after that, it should be discarded. "If after feeding your baby, you're left with half or a quarter of a bottle, put it in the fridge and offer it again at the next feeding, but that's it."
"Think about the sandwich you had for lunch. If you only ate half, you might refrigerate it and have the rest for dinner, but you probably wouldn't want to eat it for lunch the next day."
Can you freeze breast milk?
The answer is yes.
"How much [breast milk] you need to express depends on your reason for expressing," says the Australian Breastfeeding Association (ABA). Whatever your reasons you can freeze breast milk, preferably in bottles (not in ice cube trays).
Here are some guidelines from the Australian Breastfeeding Association
How long you can freeze freshly expressed breast milk
- 2 weeks in freezer compartment within fridge
- 3 months in freezer section of fridge
- 6-12 months in deep freeze
Any breast milk that was previously frozen and been thawed should either be used immediately or discarded.
Warming your breast milk
Warming up refrigerated or frozen breast milk can be done a number of ways.
If you have a few bottles of breast milk from different days, the Mayo Clinic advises you "thaw the oldest milk first. Place the frozen container in the refrigerator the night before you intend to use it."
Heating the milk too quickly such as in a microwave isn't advised. Slow, steady thawing out is best as it keeps the milk's important antibodies intact.
An article published in PLos one states that popular methods of heating breast milk create overheating which decreases the energetic value of the milk.
According to the report, many bottle warmers rise to around 80ºC. This degree of heat can cause breast milk to lose some of its beneficial lipase (fat) properties.
Warming your breast milk to 40ºC (closer to body temperature) is better as the milk denatures at temperatures above this.
Healthy breast milk, happy baby
The final issue with breast milk is the warming technique: whether you heat up breast milk in a bowl of hot water, heat it under running water, use a bottle warmer or put it in the microwave.
These methods create an uneven temperature which can also diminish the fat and lipase availability. Fats make up 45-55% of the energy in breast milk so adequate and proper heating methods should be noted.
According to the report, one way to ensure evenly heated breast milk is to stir it while it's being warmed.
For more breastfeeding information or support, call the Breastfeeding Helpline on 1800 686 268.