Do you know how to safely store and transport your expressed breast milk?

If you’re expressing breast milk, chances are you’ll need to store and/or transport it in order to feed your baby at a later time. And, just as it is crucial for your baby’s well-being that you express your milk in a safe way, so too is it vital that you store and transport it in a way that minimizes risks for your baby.

If you’re looking for information on how to safely store and transport breast milk, then read on. If you need a little help to get you started, then check out our post on   expressing breast milk.

Please note that the information included in this blog post is for informational purposes only. It should not be construed as medical advice.

Why it’s important to store and transport your expressed breast milk safely

When compared with adults, babies have very underdeveloped immune systems. As just one example, there’s an immune cell, an immunoglobulin called IgA, that’s important for fighting off the bacteria that cause gastro and babies don’t have enough of this type of cell. In fact, even a 12-month-old baby only has 15-17% of an adult level of the IgA immunoglobulin. As a result of this immune system deficiency, babies are more vulnerable than adults to a wide range of illnesses.

Perhaps the best demonstration of how easily babies can get sick is that of a baby that goes to a daycare center. You’re probably familiar with the idea that children who attend daycare frequently get sick. But did you know that children that attend daycare have been reported to have 51% more episodes of infection and 134% more days of illness than children that are cared for at home!

So, because babies are so vulnerable to illnesses, it is important that we as parents and carers take reasonable precautions to prevent them from being exposed to pathogens that have the potential to cause them serious harm. One such action we can take to keep our babies safe is to ensure we safely store and transport any expressed milk we plan to feed them.

Conditions under which it is considered safe to store and transport expressed breast milk, minimize the growth of any illness-causing microorganisms that may be present in the milk or inside the container. It is especially important to minimize the growth of these microorganisms because some of the nastiest bugs like to live and grow inside milk.

Storing milk for donation

If you’re expressing breast milk to donate to babies in need, chances are your milk will be used in a hospital. If this is the case, it’s important you seek advice from your donation contact about how to safely store and transport your expressed breast milk as hospital milk banks have their own specific guidelines for safe breast milk storage.

Storing milk for home use

If you’re expressing and storing milk for your own baby, you may use the following guidelines, which are based on the guidelines issued by the Australian Breastfeeding Association and the National Health and Medical Research Council.

5 steps to storing your baby’s expressed breast milk safely

1. Before you begin, wash your hands with soap and water.
2. Completely dry your hands with either a clean cloth, paper towel or a hand dryer.
3. Express your breast milk using your preferred method into a container that is suitable for storing breast milk. You can use glass or plastic containers. This includes baby bottles (sealed with lids designed for that purpose rather than with teats) and sealable pouches that are designed for storing breast milk (these can make it easier to store milk in the freezer). Always use a fresh container rather than topping up a container which contains milk you’ve previously expressed.
4. Label the container of milk with the date and time you expressed it. If there’s any chance the milk might be confused with another kind of milk, or any other substance, it’s a good idea to also write ‘breast milk’ on the label.
5. Immediately put the container of milk in either the fridge or freezer depending on when you plan you use it. If you’re not planning on using it within 2 days, freeze it.

Length of time expressed milk can be stored for

• Freshly expressed milk in a sterile container - Freshly expressed milk can be stored: at the back of a fridge at 5ºC or lower for no more than 72 hours; in a freezer compartment inside a fridge at -15ºC for up to 2 weeks; in the freezer section of a fridge that has a separate door at -18ºC for up to 3 months; in a deep-freeze freezer (such as a chest freezer that isn’t opened very often) at -20ºC for 6-12 months; or, if absolutely necessary, at a room temperature of 26ºC or less for 6-8 hours.
• Thawed breast milk (that was previously frozen as per the above conditions and thawed in a fridge) - Thawed breast milk can be stored: at the back of a fridge at 5ºC or lower for 24 hours; or at a room temperature of 26ºC or less until the next feed (for no more than 4 hours). Thawed breast milk should not be re-frozen.
• Breast milk that was thawed at room temperature in warm water - Expressed milk that has been thawed in warm water can be stored in a fridge at 5ºC or lower until the next feed (for no more than 4 hours). It should not be re-frozen and should not be kept at room temperature except if it’s being used for a feed immediately.

Once a feed has begun, any unused breast milk should be discarded. This is because the undrunk milk will become contaminated with microorganisms from your baby’s mouth during a feed. Safe storage conditions would minimize the growth of these microorganisms but it doesn’t take as long for the levels of harmful microorganisms to rise enough to cause illness if there are a lot of harmful microorganisms present to begin with.

How to safely transport expressed breast milk

If your baby is going to be fed expressed breast milk away from home, perhaps at daycare or on a day out with a non-breastfeeding parent, then you not only need to store the expressed breast milk safely, but you also need to safely transport it.

To do this, you’ll need to transport it in an insulated container that will keep it cool. This might be an insulated cool bag or box designed to transport baby bottles or it could be an insulated container designed to transport food. Whatever container you choose, it should be made from food-safe materials. To help keep the breast milk cool, you can also place frozen freezer blocks in the container.

It’s also a good idea to add an extra label to the container of milk stating exactly what it is. That way it can’t be confused with something else down the track if it doesn’t end up getting drunk. If the milk is being stored at a daycare center or somewhere similar, make sure you put your baby’s name on it too so it doesn’t get mixed up with another baby’s milk or formula.

Ideally, you should transport breast milk that has been frozen. When it gets to the destination, it should be placed immediately in a freezer if it’s still frozen. If it has begun to thaw, however, it’ll need to be stored in a fridge and used within 4 hours. Do not refreeze it.

If you need to transport freshly expressed breast milk, it’s best to store it in a fridge as soon as it arrives at the destination. It should then be used within 6-8 hours as you cannot be sure how cold it remained during transport.

Things to remember

• Never refreeze expressed breast milk that has been either partially or fully thawed.
• The safest thing to store expressed breast milk in is a sterilized container.
• Do not add freshly expressed breast milk to a previously expressed batch of milk.
• Don’t defrost or warm milk in a microwave. If you do, the milk may be heated unevenly creating hot spots that could burn your baby even if the bottle doesn’t feel hot from the outside.
• If you’ve warmed your baby’s milk, always test its temperature before feeding it to your baby by dripping a few drops on the inside of your wrist.
• Everyone who feeds your baby needs to know how to safely store and transport your baby’s milk so share this post with all your baby’s carers to make sure they’re in the know.