Breastfeeding and pumping milk offer great flexibility for mums, especially when returning to work or passing the baton to a co-parent. However, to ensure proper breast milk storage, there are a few important safety rules to know. In particular, storage times vary dramatically depending on whether the milk is kept in the fridge, freezer or at room temperature, and they require strict guidelines to be followed.
- Careful handling: The golden rules and exact temperatures must be followed to preserve all the nutrients, vitamins and antibodies in fresh or frozen milk intact
- A strict thawing protocol: Follow best practices to take milk from solid to liquid form, while absolutely avoiding common mistakes that encourage bacterial growth
- An optimised pumping routine: The importance of choosing high-performance, hygienic pumping equipment such as the Emy Pump hands-free breast pump to make your milk collection sessions easier.
Breast milk storage times: summary table of durations
The breast milk storage duration varies depending on the storage method you choose. Public health authorities (such as COFAM or La Leche League) agree on precise timeframes for a baby born full-term and in good health. Please note: these storage times cannot be added together
Breast milk storage at room temperature
If you plan to give the milk to your baby soon after pumping, breast milk storage at room temperature is perfectly possible. For a temperature below 25°C (or 27°C according to the recommendations), fresh, never-frozen milk can be stored for up to 4 hours (ideal) to 8 hours at most. Beyond this period, or if the room is exposed to high heat, bacteria can develop quickly, affecting the safety of the milk.
Breast milk storage in the fridge
Storing breast milk in the fridge is the preferred method for use in the days following pumping. Kept in a clean fridge at a stable temperature between 0°C and 4°C, fresh breast milk can be stored for 72 hours (ideal duration) up to 8 days (acceptable duration).
To ensure effective storage, always place your containers at the back of the fridge, in the coldest area. Avoid storing milk in the door shelf at all costs, as repeated fridge openings create significant temperature fluctuations.
Storing frozen breast milk
To build up longer-term supplies, freezing is the ideal solution. Here too, the storage duration of breast milk maternal frozen milk varies depending on the equipment used. Remember to fill your containers only up to three-quarters full before freezing.
Freezing breast milk: how long can you store it?
- In the freezer compartment of a refrigerator (freezer or combined fridge-freezer where the temperature varies around -18°C), milk can be stored for 3 to 4 months.
- In a separate freezer (an independent appliance that maintains a constant temperature of -18°C or lower), milk can be stored for 6 months (ideal duration) up to 12 months (acceptable duration).
Frozen breast milk: thawing rules
Knowing how to freeze your milk is one thing, but thawing it requires special care: to prevent bacterial growth and protect your baby, certain hygiene rules must be followed.
Storing thawed breast milk
Breast milk that has been frozen and then thawed in the refrigerator can be kept for a maximum of 24 hours in the fridge. This 24-hour countdown starts as soon as the milk is completely thawed (that is, when there are no ice crystals left inside the container).
How do you thaw frozen breast milk?
- For frozen breast milk, you must thaw it in the fridge or in a bain-marie (or under a gentle stream of lukewarm water). Never use a microwave: it destroys the immune proteins and creates uneven hot spots that could burn your baby’s mouth.
- To thaw it, place it in the refrigerator at least six hours before the planned time of use. Once thawed, gently swirl the liquid to reincorporate the fat that has separated, without shaking it vigorously.
- Always check the milk temperature before giving the bottle to your baby. To do this, you can place a few drops on the inside of your wrist.
Can you refreeze thawed breast milk?
One absolute golden rule to remember as well: you should never refreeze thawed milk. Once removed from the freezer and fully liquefied in the refrigerator, thawed milk must be consumed within 24 hours if it stays in the fridge, and within 4 hours if it is left at room temperature.
If the milk has been warmed for a feed and your baby does not finish the bottle, the remaining milk should not be kept for the next feed and must be thrown away.
Beyond simple storage times, the choice of equipment and storage method play a decisive role in preserving the nutritional qualities of your liquid gold and ensuring impeccable hygiene.
Optimising milk expression with Emy Pump
The logistics involved in managing breast milk supplies can quickly become a mental load for the breastfeeding mum. Using a portable breast pump like Emy Pump can help simplify your routine and express your milk discreetly, hands-free, wherever you are.
Cordless, discreet and slipping straight into your bra, it lets you collect your milk while continuing your work or personnel. By making regular, efficient pumping easier and hassle-free, it helps you maintain your milk supply with peace of mind. Less stress while pumping also supports the let-down reflex, which optimises the amount of milk collected.
How do you store breast milk?
To preserve all the biological qualities of your "white gold", the process starts as soon as you collect it.
- Before handling anything, it is essential to wash your hands thoroughly with soap and water. Pumping equipment must be cleaned carefully after each use, in line with official health guidelines.
- When you express your milk, make sure you use containers specifically designed for this purpose. The container should be stored in the refrigerator at a temperature of +4°C immediately after the milk has been collected.
- If you collect milk over several sessions during the same day to fill a container, make sure you chill freshly pumped milk in the refrigerator before mixing it with already cold milk. Never mix warm milk with milk that has already been refrigerated.
Storing breast milk: storage jar or storage bag, which should you choose?
To store your breast milk safely, you need airtight containers specifically designed for food contact and guaranteed BPA-free and phthalate-free. The right container mainly depends on how you plan to use it and how much storage space you have. There are two main everyday options to choose from.
Breast milk storage bags
Breast milk storage bags are ideal for freezing and offer significant space savings. These pre-sterilised single-use bags help reduce the risk of contamination but are not very eco-friendly. You can also choose reusable storage bags made from silicone. They can also be useful later on, during the introduction of solid foods, for storing purées or other foods.
Practical tip: make sure you remove as much air as possible when using storage bags for better preservation, and seal them tightly.
Breast milk storage jars
Breast milk storage jars (or storage bottles) are made of glass or BPA-free rigid plastic. They are reusable, stable, and perfect for short-term storage in the refrigerator. Some models can also be screwed directly onto certain electric breast pumps.
Storing breast milk
- To avoid waste, follow the small quantities rule: store your milk in portions of 60 ml to 120 ml, which corresponds to the average amount a baby drinks in one feed.
- When filling a jar or a bag, never fill it to the top. Breast milk is mostly made up of water and expands when frozen ; always leave an empty space of around 2 centimetres at the top of the container to prevent it from bursting under the pressure of the cold.
- Lastly, good organisation is the key to successful storage. Use a permanent marker to systematically note the date and time of expression on each container. Store your reserves using the FIFO method (First In, First Out): place the most recent bottles at the back and move the oldest to the front so they are used first.
FAQ: Answers to your questions about milk storage
My thawed milk smells rancid or soapy. Is it still safe to use?
Yes, in the vast majority of cases. This smell is due to the action of lipases, enzymes naturally present in breast milk that begin to digest fats, even at low temperatures. This is completely harmless for your baby. If the smell puts them off, you can deactivate the lipases by heating the freshly expressed milk until it just starts to simmer (around 82°C, with small bubbles forming around the sides of the pan) before cooling it immediately and freezing it.
Can I use a cool bag to transport my milk?
Absolutely. For a journey or trip, fresh or frozen milk can be transported in a cool box with ice packs. Fresh milk can be stored there for 24 hours. Make sure the containers stay in direct contact with the cold for the entire journey.
What should I do if my baby is in hospital or unwell?
The guidelines in this guide apply to a baby born at full term and in good health. If your baby is premature, unwell or in hospital, hygiene and storage protocols are much stricter to drastically reduce the risk of contamination. Don’t hesitate to discuss this directly with your doctor or the neonatal care team.
What you need to remember for proper breast milk storage
- Fresh breast milk can be stored for up to 4-8 hours at room temperature, 72 hours to 8 days at the back of the fridge (0-4°C) and for 4 to 12 months in the freezer, depending on the equipment.
- Never refreeze thawed milk; always thaw it in the fridge or in a bain-marie (never in the microwave), label your containers systematically, and never mix breast milk at different temperatures together (freshly expressed and refrigerated).
- Adding a modern, compact breast pump such as Emy Pump to your daily routine can make expression smoother and reduce fatigue and mental load.
Sources
- Recommendations on the storage of breast milk for a baby born at term and in good health, COFAM Editorial Committee, January 2024, French Coordination for Breastfeeding (COFAM). - Link
- Breast milk: Practical storage guide, Ministry of Health and Sports, October 2013, public information leaflet - Link
- Breast milk storage, Clinical Issues: Breastfeeding, January 2022, La Leche League France. - Link
