Breast milk storage

Many women express breast milk at some point during their breastfeeding period. And some women hand-express during the last part of their pregnancy - for example, it can be smart if you have (gestational) diabetes and your baby therefore needs a supplement of milk right after birth. By expressing, storing the milk and bringing it with you to the birth, you can ensure that your baby gets your golden drops of milk.

The same applies in your months with breastfeeding of baby. By expressing, you can ensure that baby gets your super nutritious milk instead of formula. For example, you may have to go to work, need baby care, or something else.

And then there are more who need to store their breast milk because they have excess milk. This may be due to a large milk production that they want to save for later (e.g. to care for a baby) or a desire to donate to those who do not have (as much) milk. This may be via the hospital or in informal networks.

Regardless of the reasons for expressing milk, it is important for health reasons to handle and store the milk properly.

Hygiene before milking

Regardless of the method you use to express milk, good hygiene is important. Wash or sanitize your hands before expressing milk to minimize the risk of transferring bacteria. If bacteria are transferred from your hands, it can lead to increased bacterial growth in the milk, which affects both the protein content and the shelf life of the milk.

It is also important to be careful when cleaning the milk containers and the parts of the breast pump that come into contact with the breast and milk. Wash with water and neutral detergent and then scald with boiling water.

If you use a breast shell to collect milk, more skin bacteria will be mixed in. It is best to use that milk immediately afterwards.

There is no need to clean the chest.

Storing expressed breast milk

Often, expressed milk does not need to be used until some time after it has been expressed, so it is important to know how to best handle and store it.

Expressed milk must be cooled if it is not to be used within a few hours. If the quantities are small, you can cool the milk in the refrigerator, otherwise the milk can be cooled in a cold water bath. If you milk small portions at a time, you can advantageously collect them in a slightly larger portion - however, be sure to note the first day of expression in terms of shelf life. For example, if you milk on Saturday and Sunday and mix the milk together, write Saturday on the container.

If you freeze the milk, remember to do so in portion sizes approximately equivalent to one meal.

In general, the longer the milk is to be stored, the more important it is to take care of hygiene.

Below is a list of shelf life:

Fresh, expressed breast milk:

• In the freezer (approx. -18 degrees): Ideal shelf life 6 months, usable for 12 months
• In the freezer compartment of the refrigerator (down to -18 degrees, but often warmer): 3-4 months
• In the refrigerator, at the back (max 5 degrees): Ideal shelf life 72 hours, usable for 5-8 days
• In a cooler bag with cooling elements (transport at max. 15 degrees): 24 hours
• At room temperature (16-29 degrees): Ideal shelf life 4 hours, usable for 6-8 hours
• Breast milk that has been thawed slowly in the refrigerator (milk thawed more quickly, e.g. in a water bath, should be treated as warmed milk):
• In the refrigerator, back (max 5 degrees): 24 hours
• At room temperature (16-29 degrees): 4 hours
• Should not be refrozen or stored in a cooler bag.
• Thawed and heated breast milk (before the meal has started):
• In the refrigerator, back (max 5 degrees): 4 hours
• At room temperature (16-29 degrees): Until the meal is finished (should not be stored)
• Should not be refrozen or stored in a cooler bag.

Thawed and heated breast milk (after the meal has started):

• At room temperature (16-29 degrees): Until the meal is finished – the milk should be discarded immediately afterwards and not stored.
• Should not be refrozen or refrigerated again, neither in the refrigerator nor in a cooler bag.

Always check if the milk is good before giving it to the baby. Smell and taste it. If it is sour, it should be discarded.

The appearance of breast milk

The appearance and viscosity (thickness) of your milk varies over time, from before birth, in the days after birth, and in the remaining months (perhaps years) that you breastfeed. The appearance and viscosity of your milk also varies throughout each feeding and from day to day.

Fresh breast milk separates into milk and cream - just like untreated cow's milk does. The colors can vary widely from yellow, bluish, off-white, white and almost orange. This is completely normal.

Storage containers intended for breast milk

Breast milk can be stored in plastic and glass containers approved for food use.

Very small portions, such as those to be taken to the delivery room, can be stored in small syringes (without a needle), medium portions can be frozen in small or larger jam jars, large portions can be stored in freezer bags - remember that liquid expands when frozen, so do not fill the containers completely. Always put the date and year on the label so that there is no doubt about the shelf life.

Thawing frozen breast milk

The most gentle method of thawing is to leave the milk in the container overnight in the refrigerator. This will thaw the milk slowly and retain as much of its super properties as possible.

The next best solution is to thaw the milk under cold, running water. This method is especially good for smaller portions.

The last option for thawing is to place the milk in its container in a warm water bath - for example in a bowl with a maximum of 40 degrees Celsius of warm water.

It is not recommended to thaw breast milk in a microwave, as research shows that the microwave affects the content and nutritional value of the milk.