Instructions For Breast Pumping Milk Storage Properly And Safely 

 September 16, 2022

By  Mei Lele

If you will be away from your baby for an extended period, pump or manually express your milk while you typically breastfeed your baby. This will assist you in maintaining your milk supply so that you can continue breastfeeding even if you return to work or school. 

Plus, breast pumping milk storage safely and adequately will ensure that your baby absorbs all the essential nutrition while you are away. This also guarantees your baby’s health.

Ways To Store Breast Pumping Milk Safely

Store Breast Pumping Milk

Aim to help mothers ensure a source of nutrition for their little ones. The method is usually applied to express milk to stimulate or store milk for newborns to use gradually. However, you should note the following:

  • Do not store leftover milk or mix it with freshly pumped milk to ensure the hygiene and quality of milk for babies.
  • Once breast milk is expressed or pumped, it should be refrigerated or frozen immediately. If it is impossible to refrigerate or freeze breast milk immediately, you should try to store breast milk in a cool place.
  • Plus, limit the opening of the refrigerator door a lot and do not store breast milk in the door because it makes the temperature in the refrigerator unstable, quickly affecting the quality of milk and the baby's health during the process of using frozen milk.
  • Besides, stored breast milk must be expressed in a clean and hygienic environment: if expressing milk by hand, the mother's hands must be kept clean, and if expressed with a breast pump, the parts of the breast pump need to be cleaned, disinfected, and kept dry.
  • Breast pumping milk storage containers should be cleaned and disinfected after each use. You can use a specialized sterilizer to disinfect or rinse with boiling water. If sterilization requires drying, a sterilizer with a drying function can be used, or the item can dry naturally.

Before Pumping Breast Milk

The hygiene element is very important when storing and preserving breast milk and during the initial pumping or pumping step. The mother should note the following before expressing or pumping milk:

Store Breast Pumping Milk
  • Wash your hands thoroughly with soap and water, or use an antiseptic hand sanitizer containing at least 60% alcohol.
  • You can express breast milk by hand, with a hand pump, or with an electric pump.
  • If you use a pump, check the pump kit and hoses for cleanliness. Throw and replace immediately if tubes are moldy or not clean.
  • Wipe the buttons, power switch, and pump surface with a cloth moistened with a safe cleaning solution.

Store Breast Milk After Pumping

Breast milk storage items is one of the factors affecting the best breast milk storage. Nursing mothers should only store milk in the following containers:

Choose The Suitable Milk Bottles Or Bags

  • Use a specialized breast milk storage plastic bag, clean glass bottles, or plastic bottles to store pumped breast milk. Also, you must have tight-fitting lids. You can buy these items at a reputable supermarket or pharmacy.
  • Most importantly, before use, clean the bottle with warm water and let it dry. When putting milk in the bottle, it should not be filled but leave a space. Plus, do not store milk in cracked or cracked bottles.
  • Avoid using plastic bottles with the recycling symbol number 7 because these bottles can be made of BPA-containing plastic. Since it can be harmful to the health of babies.
  • Do not store breast milk in disposable bottles or regular plastic bags that are not specifically for storing breast milk.
  • You should choose a bag with about 60 - 120ml to store breast milk. When pouring milk into the bag, avoid overfilling; leave space because milk is liquid, so it will expand as it freezes.

Storage Time For Breast Milk

In fact, many cases of babies cannot breastfeed directly, so mothers have to express or pump milk. Therefore, the problem of preserving breast pumped or expressed milk at room temperature is how many hours can be left out?

Thus, it is always a concern for many breastfeeding mothers. So how many hours does breast milk last? Hence, WHO and UNICEF have given recommendations to answer the question of how long breast milk should be stored as follows:

Types of Brest Milk

Storage Temperature

Storage Time Limit

Newly pumped or expressed breast milk out in the open

Room temperature
(up to 77° F)

Up to 4 hours if not
in direct sunlight

Cooler or
insulated bag
with frozen
ice packs


Up to 24 hours

Newly pumped or expressed
breast milk in
the refrigerator

About 40° F

Up to 4 days, ideally
stored in the back of
the fridge


About 0° F

  • Up to 12 months is acceptable
  • You should store it in the back of the freezer
  • Within 6 months is the best choice for you

Thawed breast
milk in the

About 40° F

  • Use within 24 hours
  • Don’t refreeze breast milk after you thaw it

Thawed breast
milk out in
the open

(up to 77° F)

  • Use within 2 hours
  • Never refreeze breast milk after you have thawed it
How Long Does Breast Milk Last At Room Temperature?

The kind of breast milk will determine how long it can keep at room temperature.

  • If not in direct sunlight or near other sources of heat, you can keep freshly pumped breast milk at room temperature (no warmer than 77° F) for up to four hours.
  • Thawed and previously frozen breast milk can be kept at room temperature for one to two hours. After this time, you should throw it out.

If your newborn has leftovers after feeding and does not complete the bottle, it must be utilized within two hours. You must discard it after this period of time because there are too many germs!

You should store breast milk in small quantities and with small capacities so that your baby consumes the entire amount at each feeding. This might help avoid wasting breastmilk.

How Long Does Breast Milk Last In The Fridge?

The kind of breast milk will determine how long it may be stored in the refrigerator:

  • Freshly pumped breast milk may be kept at the back of the refrigerator (39° F or 4° C) for up to four days. Most importantly, when you need breastfeeding, don’t forget to take it out to use.
  • Breast milk that has been previously frozen and thawed can be kept in the refrigerator for up to 24 hours before being discarded. No mother wants that! Therefore, the moms only take the right amount of milk for the baby at each feeding. After breast milk has thawed, you shouldn't refreeze it again.

Once more, if your baby has any leftovers after feeding, it must be consumed within two hours.

How Long Does Breast Milk Last In The Freezer?
Store Breast Pumping Milk

The best time limit to use breast milk is within six months. However, you can also keep it in a refrigerator with a separate freezer for up to 12 months at 0°F or 18°C.

Moreover, moms should use breast milk as soon as possible since storing it for a long time will reduce its vitamin C. Your freezer should be set to a temperature of around 0° F. The ideal way to store it in the freezer is at the rear, farthest from the door, where temperatures are most constant.

Tips For Storing And Preserving Breast Milk In The Refrigerator
  • Specify the milking date on the label and stick it on the container, add the baby's name if the milk is delivered to a childcare facility.
  • Do not store breast milk in the freezer’s door of the refrigerator because the temperature will change when the door is opened and closed. It should be placed in the coldest place in the milk storage cabinet and be limited to moving or arranging unless taken out for use.
  • If it is determined that the fresh breast milk pumped or expressed that you don't use within the next 4 days, it should be frozen immediately to help preserve the quality of the milk.
  • To avoid wastage due to not utilizing it all, store breast milk in modest quantities in each bottle, roughly 60-120ml comparable to the amount your baby will consume in each feeding.  Besides, the small volume storage also helps the milk freeze faster and shortens the time it takes to defrost breast milk.
  • When freezing breast milk, you need to leave some space, do not fill the container because the milk expands when it freezes.
  • In case of traveling, you can store breast milk in an insulated container with an ice pack for up to 24 hours. When you arrive, use the milk immediately or put it in the fridge for storage.

Guiding Defrosting Frozen Breast Milk Safely

Store Breast Pumping Milk

Follow the first-in, first-out principle: Always defrost the bottle with the longest expressed date on the label, as the quality of breast milk can degrade over time.

Thawing Refrigerated Breast Milk

  • Before giving it to your baby, take the milk out of the refrigerator and soak it in warm water at 104.00 ℉ until it reaches the right temperature for your baby to feed.
  • Do not use water that is too hot to soak milk because it will lose vitamins and minerals in breast milk.
  • Breast milk that has been taken out of the refrigerator should not be refrozen, so the mother only takes the right amount of milk for the baby at each feeding.

Thawing Frozen Breast Milk

  • Mothers should put frozen breast milk in the cool refrigerator compartment overnight or 1 day before use to defrost but still keep a cold temperature. If quick defrosting is required, place it in a basin of warm water or under warm running water.
  • When the milk has turned from hard to liquid and completely soft, mothers gently shake the milk to mix the high-fat whey and milky parts together. After that, continue to change the warm water to soak the milk until the temperature is suitable for breastfeeding.

If there is a cloudy white precipitate after defrosting breast milk by moving it from the freezer compartment to the cooler compartment, the milk is spoiled and cannot be used.

Conversely, if there is a thin layer of scum floating on the surface of the bottle, the milk is still usable. This thin layer is the essential fat in breast milk. The mother just needs to gently shake the film to dissolve it in the milk before giving it to the baby to suck.

Some Important Notes When Defrosting Breast Milk

Frozen breast milk shouldn't be defrosted at room temperature: Bacteria can get in if you thaw breast milk at room temperature, so thaw it only in the fridge.

Do not defrost breast milk by heating it or using the microwave: High heat, microwaves, and electromagnetic waves destroy the essential nutrients, enzymes, and immune antibodies of breast milk.

Avoid shaking the defrosted bottle aggressively or making sudden temperature adjustments: Breast milk will lose the function of antibodies and proteins that protect the baby's body. Plus, it will lose some of the nutrients in the milk if it is shaken vigorously or has a sudden change in temperature.

After thawing, store breast milk at room temperature for up to 4 hours or in the refrigerator for up to 24 hours. If your baby doesn't use up all the defrosted milk in 24 hours, you can throw away the leftover milk.

Frequently Asked Questions

Store Breast Pumping Milk

When the milk comes in a lot, the mother can pump it out and store it for your baby to use later. However, how long can breast milk be stored in the refrigerator after being pumped? Is it safe for babies to use? How do know if it's spoiled or not? Let's find the answers to your questions!

Is Frozen Breast Milk Good?

Many nursing mothers choose to freeze breast milk to help stimulate more milk production and facilitate breastfeeding. It is convenient when the mother is busy or the baby cannot directly feed on breast milk.

Frozen breast milk, even though it is expressed from the mother's breast, is not as good as breastfeeding directly because freezing will lose the lipase enzyme to digest fats, significantly reducing the number of other components that are resistant to infectious diseases.

Besides, depending on the age of the baby, the composition of breast milk will also change to suit the needs of the child's development, so children using frozen milk for a few months may no longer be suitable for age needs.

However, the use of frozen breast milk for babies can affect the health of children, typically gastrointestinal infections if breast milk is not frozen properly.

Does Frozen Milk Change Color?

Frozen milk will have a slightly different color than freshly pumped milk. Usually, frozen breast milk will turn bluish, yellow, or brown when refrigerated. It is a normal thing, so you can rest assured of that.

Breast milk stored in the refrigerator or freezer will be separated before giving it to the baby. The mother just needs to shake it gently to mix them together.

Can You Add Fresh Breast Milk To Already Frozen Breast Milk?

It is absolutely fine to add freshly expressed breast milk to frozen milk or breast milk to keep it refrigerated. But before adding it to the old milk, it is necessary to chill the freshly expressed or pumped milk in the refrigerator or quick ice chiller for at least an hour.

Never add warm and freshly pumped milk to frozen milk as it will thaw the frozen milk and keep the milk separate for each day.

Why Does Frozen Milk Have A Strange Smell?

The process by which the enzyme lipase inhibits the growth of harmful bacteria leads to reactions that break down fats and release fatty acids that sometimes change the scent of breast milk, causing frozen milk to have a strange smell.

Nevertheless, moms can rest assured that babies can still use flavored frozen milk normally without harm if the mother freezes it properly.

breast pumping milk storage


On the whole, there are various factors that affect breast pumping milk storage. For example, the content of milk, room temperature, the regulated temperature in the milk storage fridge, and the cleanliness of the environment. 

All those elements can affect how long breast milk can be safely stored. While freezing can keep food safe for a very long time. However, following the recommended shelf time and storage requirements for breast milk is important to ensure breast milk has the best quality for your baby.

Hence, properly storing breast milk seems simple, but if moms do not learn to store breast milk carefully, it is very easy to make mistakes that affect the quality of the breast milk and the health of the newborn.

Therefore, every mother needs to be equipped with the right knowledge about breast pumping milk storage to ensure the most abundant and safest nutrition for the baby.

Mei Lele

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