Tanks of decanted frozen milk form a Breast Milk Bank for your baby. Given that most of the components and proteins of mother’s milk retain their biological activity when unfrozen, the value of «contributions» for the health of the baby is indisputable and irreplaceable.
You can store the milk at low temperatures (-20 degrees) for up to 3-6 months in convenient portioned containers.
You can thaw your breast milk and feed it to your baby as needed.
When it is necessary to give express milk from the refrigerator:
- Hypogalactia, insufficient breast milk production or a temporary decrease in breast milk production;
- Lactostasis;
- Flat or inverted nipples that make it impossible to grasp the breast properly without special pads;
- A lethargic or weakened baby;
- Cracked nipples or painful sensitivity;
- Feeding twins or triplets;
- The need to work or study;
- A woman taking medications that are incompatible with breastfeeding;
- Medical conditions on the part of the mother or child.
In any of these situations, it helps to know how to properly express, freeze, and store breast milk in the freezer, and how to use frozen breast milk.
How to express breast milk correctly for storage
- If your baby is suckling sluggishly or has lactastasis, it is best to pump by hand.
- If your baby won’t latch on at all, it’s best to use a breast pump.
Both methods can be combined. For more details — Pumping.
Use a specially prepared (sterile) clean container. You can use glass or enamelware. Special containers for breast milk are best.
You can sterilize the container, for example in the microwave oven for 2-3 minutes, and not use it for other purposes.
How to store express breast milk?
Breast milk should be stored in:
- Clean glassware;
- Special plastic bags;
- Special containers.
The key to maximizing the preservation of all the useful qualities in storage is the cleanliness and sterility of the utensils for expressing and storing milk.
The table below shows how long the express milk can be stored:
Method of storage | Temperature | Recommended storage time | Allowable storage time | Note |
At room temperature | 16-29°С | 3–4 hours | Up to 6 hours | - |
Cooler bag with cooling elements | - | - | Up to 24 hours | Make sure that the container with the milk is in constant contact with the cooling elements. Place in the refrigerator as soon as possible. |
Fresh milk in the fridge | 4°С or less | 3 days | 5–8 days | Store at the back of the refrigerator |
Frozen milk that defrosts in the refrigerator | 4°С or less | - | Up to 24 hours | Store at the back of the refrigerator |
In a freezer with a door separate from the refrigerator or in a separate freezer (deep freezing) | -18°С or less | 6 months | Up to 12 months | Store at the back of the freezer |
Expressed breastmilk can be stored:
- at room temperature 16-29 degrees Celsius for up to 6 hours.
- Store in the refrigerator for up to 8 days at a storage temperature of 4 degrees Celsius or lower
- In a freezer with a door separate from the refrigerator or in a separate freezer for up to 12 months.
How long you can keep express milk in the refrigerator — nuances
If you plan to use the milk soon, you can store it in a sealed container near the back of the fridge for 6-7 days, but only if the temperature is below 4 degrees Celsius.
If you want to freeze your decanted milk in a bottle stored in the refrigerator, you can do so after no more than 24 days, as long as the storage temperature is 4-6 degrees Celsius. Sign the containers with the date and time, so you will know exactly what to do with each individual serving.
- Portions of milk not used within a day can be mixed together in suitable containers and frozen.
How to properly freeze breast milk and how to store breast milk in the freezer to create a Breast Milk Bank?
- If a Breast Milk Bank is being created, to properly freeze breast milk, immediately after expressing it, chill it in the refrigerator for 30 minutes and then place it in the freezer…
- If it is not possible to fill the container completely, you can freeze as is, and then add the chilled milk to the frozen milk, provided that the volume of added milk is less than the frozen milk, to avoid defrosting the latter.
- Before freezing, be sure to write the date and time of decanting on a label we put on the storage container so you know how long the breastmilk will last in the container.
How do I store my breast milk?
The temperature range is given in the table above.
It is better to give it in small portions. When feeding, the baby naturally releases bacteria into the cup or bottle. Therefore, you should not store underserved milk for more than one hour, you will have to pour it out.
Women’s milk, like mammalian milk, tends to separate into layers when stored, and the fattier part of it as cream rises to the top. Therefore, you should stir the milk in the bottle before feeding the baby. It is important to do this gently, without a lot of shaking, so as not to destroy some of the protective and nutritive components.
Healthy, full-term babies can drink milk at room temperature, but it is still best to warm the breast milk when it has been pumped to body temperature.
How do I use frozen breast milk?
Unfrozen breastmilk should not be frozen again, and it should not be stored for more than a day. Think about this ahead of time and distribute the milk in small containers of 60-120 ml. This way if the milk is stored and used in small portions, completely, it will not go to waste. Milk left over after feeding cannot be reused.
Remember that chilled milk has more antibacterial properties than frozen milk. Therefore, you should use chilled milk first, and then frozen milk.
Residual activity of some components of breast milk after freezing for 3 months at -15°C:
Milk component | Residual activity % |
Secretory immunoglobulin A | 100% |
Lactoferrin | 100% |
Lysozyme | 90-100% |
oligosaccharides | 100% |
Omega 3 and Omega 6 PUFAs | 100% |
Potassium, calcium, magnesium, phosphorus | 100% |
Vitamin A | 100% |
How to thaw breast milk correctly
In order for the milk to retain its beneficial properties and remain safe for the baby, it must be defrosted properly.
- It takes +- 12 hours to defrost breast milk in the refrigerator.
- To defrost breastmilk quickly, put the container under running warm water (not over 37 °C).
How to reheat express breast milk
- Gently shake the container.
- Pour into a suitable container — a bowl, a pot or a cup, warm water of 35-40 degrees Celsius (try a drop on the inside of your wrist)
- We place the container with the milk in the prepared container.
- Wait until the milk in the container gradually becomes the same temperature as the water outside.
The best way to warm breastmilk in a bottle is in a bottle warmer
You can take it out an hour before you drink it and place it in a container of warm water at room temperature.
IMPORTANT — the microwave does not heat liquids evenly and your baby can get burned, and important live components of the milk are likely to be destroyed.
How to give your baby express milk from the refrigerator.
You should check the temperature of the milk before giving it to your baby, either by dropping a drop on your wrist or from a spoon, or by putting the bottle to your cheek.
DO NOT taste the milk directly from the bottle-your oral bacteria will go straight into the milk.
How long does breastmilk keep after defrosting?
Once thawed completely, breastmilk can be kept at room temperature for 2 hours and in the fridge for up to 24 hours if it’s under 4 degrees.
How long can I keep breastmilk after you defrost and reheat it?
- Leftover defrosted and heated milk can only be used the next time you feed your baby, because you can only keep it in the refrigerator for 4 hours after defrosting and heating.
- If your breastmilk has been at room temperature for two hours after defrosting, you should pour it out, even if you haven’t had time to feed your baby.
- Thawed milk should not be refrozen.

Elena Demchenko graduated from Donetsk Medical Institute named after M. Gorky with a degree in pediatrics.
Work experience in medicine: district pediatrician, neonatologist of the department of nursing extremely premature babies, joint stay of mother and child, resuscitation and intensive care of newborns.