The guidelines that follow apply to milk that will be give to full-term healthy babies. If your baby is premature or sick, hospital staff can give you information on stricter storage guidelines, to ensure your baby gets as much benefit from your milk as possible.
Cleanliness
Good hygiene is important when storing your milk. Reduce the risk of contaminating your milk by:
- Washing hands before expressing or handling milk
- Keeping your pump clean, using hot soapy water for all parts which come into contact with your milk. Some mothers sterilize as well
- Keeping your fridge, freezer, cool bag and icepacks clean
- Placing containers of milk in a clean bag or lidded box before storing
- Keeping your milk away from meat, eggs, etc
Storage containers
Hard-sided containers, either glass or plastic, do the best job of protecting your breastmilk. Avoid containers made with the controversial chemicals bisphenol A, identified with a number 3 or 7 in the recycling symbols. A safer alternative is polypropylene, which is soft and semi-cloudy and marked with a 5 or letters PP.
- Use containers with well-fitting tops
- Wash containers in hot, soapy water, rinse well, and allow to air-dry before use. Or wash and dry in a dishwasher
- Leave 2.5cm of space at the top to allow the milk to expand as it freezes. Plastic milk storage bags, designed for freezing breastmilk are convenient and take up less room in the freezer
- Avoid bags that are not designed for freezing- they may burst or or tear. Double bagging can prevent accidents
- Some milk storage bags can be attache directly to a breast pump, so you can collect and store milk in the same container
- Allow 2 to 3 cm for the milk to expand when frozen and squeeze out the air at the top before sealing
- Stand the bags in another container on the fridge shelf or in the freezer
Remember to date the containers- it can help to put a use-by date too. Add your baby's name if he/she will receive the milk at childcare or a nursery.
How much milk will I need?
Store milk in 60 to 120ml (2-4oz) quantities to avoid waste, at least until you know how much milk your baby takes at a feeding. Small quantities thaw quickly and can be combined if needed. You can also store smaller quantities of 30ml for when your baby is extra hungry, or wants to be fed just before you're due back.
You can combine milk pumped at different times, if you:
- Cool fresh milk for 30 min in the fridge first
- Add fresh milk to frozen milk only if there is less fresh milk than frozen
- Use it within the time limit of the oldest expressed milk
Looks are deceptive!
It's perfectly normal for expressed milk to look thin, bluish, yellowish or even brownish in color and for it to separate into a milk layer and a cream (fat) layer when stored.
Preparing to use
Thaw and heat with care
High temperatures or even moderate temperatures over a period of time affect many of the beneficial properties of breastmilk, so:
- NEVER warm breastmilk in a pan on a stove
- NEVER warm breastmilk in a microwave
Microwaves do not heat liquids evenly, so there may be hot spots in the container of milk, and this can be dangerous for babies.
Defrosting frozen breastmilk
Your milk can be deformed in the fridge, avoiding unnecessary heating. Use within 24 hours. BREASTMILK CANNOT BE REFROZEN ONCE THAWED.
To defrost your milk more quickly:
- Hold the container under cool running water and gradually increase the temperature of the water to heat the milk to feeding temperature
- Immerse the container in a bowl of warm water, Take the milk out and reheat the water if necessary. Do not stand in a pan of water heading on the stove
Refrigerated Milk: Warm for a few minutes under a tap or in a container of water. Test for temperature on the inside of your wrist.
Avoid contamination: Dry the containers before opening, with paper towels or a clean tea towel.
Breastmilk separates naturally: Gently swirl the container to remix. (see my post on swirling vs shaking here)
Storage
Breastmilk is remarkably resilient - it stores well due to its antibacterial properties.
Temperature: Store milk in the coldest part of fridge and freezer. Self-defrosting freezers can have warm spots. Use fridge and freezer thermometers to determine where the temperature is most constant. The fresher your milk, the better.
Milk stored in the fridge will have more goodness than frozen milk. Some of the anti-infective properties are lost when milk is frozen- but it still helps protect babies from diseases and allergies and is far superior to any formula. Although you probably won't plan to keep your m ilk in the fridge for set or eight days, it's good to know you can use safely any you find hidden at the back of the fridge. When your baby gets your milk within a few days of being refrigerated, its's also reassuring to know it is well within its usable limits.
Keeping milk for the next feed
Some sources will tell you to throw away leftover frozen or heated milk, which will have lost some of its antibacterial properties. Instead, check out this post for some ideas on what to use breastmilk for that is no longer safe for consumption. It isn't known how safe it is to keep fresh breastmilk left in the bottle after a feeding. It should certainly be used within 1-2 hours. Avoid eating previous milk by offering small amounts at a feeding.
Away from home
Expressed breastmilk can be kept in a common fridge at work or at the childcare center. Label clearly. If a fridge isn't available, place it in an insulated container with deep frozen icepacks. With enough icepacks, milk will stay at fridge temperatures for us to 24 hours. Icepacks are also useful when carrying milk home from work or to childcare, especially on warm days. But breastmilk can be safely refrigerated or frozen after shortchanged periods of storage at hight temperatures.
Soapy smell? Rancid smell?
If you plan to store large amounts you could try freezing a small batch for a week before defrosting and tasting it. Some mothers notice their milk smells slightly soapy once defrosted, sue to high levels of lipase, the enzyme that breaks down fat. The milk is still safe to use but some babies refuse to drink it. Heating milk to a scald (bubbles around the edges, not boiling) then quickly cooling it before freezing can deactivate the lipase.
Thrush
Freezing deactivates yeast but doesn't kill it, but there is no current evidence the milk frozen when you and your baby have thrush with reinfect you later.
There isn't yet complete agreement about storage times. But it's always preferable to store milk for as short a time as possible to ensure:
- Minimal growth of bacteria
- Minimal loss of antibodies and nutrients
Laboratory studies have shown that breastmilk becomes less resistant to bacteria with time, but most of the bacteria found in breastmilk are harmless skin bacteria and not illness-causing ones.
The longer you store your milk, the more care you need to take about:
- Cleanliness while expressing, storing and handling milk
- Storing milk at appropriate temperatures (use fridge and freezer thermometers)
- Checking for bad taste and smell, which will show if your milk has gone off. If milk has gone bad, consider using it for other uses as mentioned in this post.
If any family members are ill, especially with scenes and diarrhea, your baby will be better off with fresh milk rather than frozen. The most recent milk from your stores will offer him/her the best protection from the illness. You may prefer not to freeze your milk until everyone is better.
Source: https://www.laleche.org.uk/storing-your-milk/#fulltermbaby written by Karen Butler, Sue Upstone and mothers of the La Leche League Great Britain
