Storing breastmilk

You can keep your milk and use it when needed, so that you don't deprive your baby of the best food. Milk that is properly collected and stored does not change its properties and is safe for the infant.

You may find yourself away from home for several hours and unable to breastfeed your baby. You may have to work longer or travel, your older child may be sick, you may want some free time for yourself; besides, it is more and more common for mothers to be required to return to work very soon after giving birth. Your milk stored in the refrigerator or freezer does not change its nutritional properties or taste.

Preparation for milk storage                                                       

Storage begins with the expression process - manually or with a pump (manual or electrical). Breast pumps are excellent, because the milk is collected directly in a sterile bottle that comes with the pump, so there is no contamination with external bacteria; milk in such bottles can be stored and kept until a meal.                                                          

Always express milk with clean hands! Wash your hands with soap and water; it is not necessary to wash your breasts before expression. Wash the milk containers with detergent in hot water, rinse them well and air dry them or use paper towels. The use of disinfectants is not recommended. Wash and disinfect the breast pump according to the manufacturer's instructions. To store milk, use hard plastic or glass containers with a tight lid, or bags specifically designed to store breastmilk. Plastic containers are better than glass ones for preserving all the milk ingredients.  Plastic used for baby bottles should not contain harmful bisphenols! Disposable plastic bottles or urine culture containers are not recommended, because their chemical safety is not reliable.

Proper storage of milk is extremely important in order to preserve the nutritional and anti-infective properties of breastmilk and prevent contamination with external bacteria. Milk can only be used if stored properly!

Storing freshly expressed breastmilk

At room temperature: OPTIMALLY NO MORE THAN 4 HOURS. If you will not use the milk for a long time, it is best to keep it in the refrigerator. In the refrigerator: 24 to 72 hours; not in the door, but further inside, where the temperature is constant and does not exceed 5ᵒC. If you plan to store milk longer, it is best to freeze it.

Cold milk is heated in warm water by immersing a bottle of milk in a bowl of hot water. You can also use a bottle warmer.  Expressed breast milk is not homogenized, so it is normal for it to separate into two parts - fat and water. Before checking the temperature, shake the container with the milk to distribute the fat in the milk.

NEVER heat breastmilk in the microwave or directly on the stove. High temperature destroys some valuable ingredients, and the child may get burnt with unevenly heated milk from the microwave oven.

Freezing milk

  • You can freeze expressed milk. To avoid discarding unused milk unnecessarily and to facilitate thawing and heating, store it in containers of 30 to 120 ml.
  • Before storing it, mark the milk collection date on the containers. Milk expressed during multiple sessions during the day can be combined in one container.
  • Avoid adding freshly expressed milk to milk that has already been cooled or frozen - you need to cool the new milk first before adding it to the milk expressed beforehand.
  • If you use bags, keep them in a closed plastic container, to avoid absorbing the smells of other food from the freezer.
  • You can also use milk prepared in this way to prepare baby purées when the time comes.

Storing milk in the freezer

  • Compartment in the refrigerator: up to two weeks
  • Vertical freezer with a separate door: 3-4 months
  • Freezer with constant deep freezing at -19 °C: up to 6 months

Smell of frozen milk

Frozen milk, as well as that stored in the refrigerator, may have a smell different from fresh milk, due to the process of fat decomposition under the influence of enzymes from milk. There is no evidence that babies tend to refuse this milk because of the smell.

Defrosting milk

  • You can slowly thaw the milk in the fridge (it takes about 12 hours; put it in the fridge the night before you plan to use it). Avoid leaving frozen milk at room temperature to thaw.
  • If you need faster thawing, you can put the container with frozen milk under a stream of water (first cold, and then gradually increase water temperature).
  • Thawed milk can be stored in the refrigerator for up to 24 hours after it is completely thawed, and at room temperature for a maximum of 2 hours. Once thawed, do not refreeze milk!

Transport of expressed milk

Use a heat-insulated cooling bag and cooling cartridges to transport expressed milk. You can transport fresh or frozen milk. As soon as you arrive at your destination, transfer the milk to the refrigerator. If frozen milk has thawed, use it within four hours and do not freeze it again.

These recommendations apply to the storage of milk for a healthy baby born at term, for use at home. If your baby was born preterm and/or hospitalized, be sure to consult a doctor for guidelines on how to store milk in that case!