Preparing and storing breast milk guidelines for beginners

Breast milk in storage containerOnce you get over the hurdle of learning how to breast pump, there is still one big question that remains…what to do with all that liquid gold?

The CDC has very thorough storing breast milk guidelines and common situational questions that might arise on your journey of feeding bottled breast milk. I strongly recommend reading through all of their information and FAQ page. I referred back to it several times before I remembered all the details.

For those who are short on time, I have condensed the information they provide for you. Also included are some other helpful tips and information regarding breast milk below.


Here are a couple basic safety items when it comes to breast milk…

Timing (In general):

– Breast milk is good for up to 4 hours left at room temperature if freshly pumped (warmer climates may affect this)

– Breast milk is good for up to 4 days stored sealed in the refrigerator (it is best to keep the milk in the back of the fridge, not the door)

– Breast milk is good for 6 months in the freezer (up to 1 year is considered acceptable)

– For refrigerated or frozen breast milk that has been reheated, it is good for up to 2 hours left out. Do not put it back in the fridge or freezer for using later. It should be discarded if not consumed after that time frame.

– For frozen breast milk, if it is thawed in the refrigerator, it is good for up to 24 hours once defrosted


– Always wash your hands prior to handling breast milk. Not washing your hands could potentially spread germs to your little one

– Always thoroughly clean and dry bottles and cups…another way to significantly reduce the spread of bacteria

– Breast milk should be stored in a sealed container or bag to prevent the possibility of contaminating the milk

Click here to view the CDC complete brochure on storage and preparation of breast milk

Storing milk from different pumping sessions

I know it may be tempting to save on milk bags by combining milk from different pumping sessions. But something you need to think about is the temperatures of the milk. If the bag has already been placed in the refrigerator, then the contents would be cold. When you add fresh milk to the old bag, it rewarms the cool milk.

If you want to mix milk that was pumped at different times, you would want to cool the freshly pumped milk first before combining. This could also affect how long that batch was good for since some milk is older and some is newer.

I found it easiest to just use a new bag or container each time I pumped. This way I didn’t risk compromising the integrity of the breast milk.

How to warm breast milkBreast milk bottle warmer

The easiest way to warm breast milk would be to use warm water. You would want to either put the bottle under running warm water (not hot) or place the bottle in a bowl full of warm water. The downside to this is it can take several minutes for the milk to heat up. Anyone that has a hungry and/or upset baby may want a faster way to prepare the milk.

Alternatively, you can purchase a bottle warmer that can accomplish this goal a bit faster. You just want to be careful not to forget about it, as these can get pretty hot fast if your not mindful of it. Scortching the milk can kill valuable nutrients.

Here are a few dos and don’ts to keep in mind:

– Keep the container or bag sealed while warming

– Aim to heat the milk to approximate body temperature

– Test the temperature of the milk with a few drops on your wrist prior to feeding


– Use boiling water or the microwave to heat the milk

Now that we have the basics covered, we can get into a couple fun tips that can save space and time!

Freeze milk storage bags laying flat

Flat frozen milk bags in freezer

As my husband and I were interviewing daycare facilities, one of the workers gave us the advice to freeze the milk bags laying flat, instead of standing up on end.

This is beneficial in two ways:

One: They are easier to stack in the freezer. She even suggested using an empty soda can box to sort them in order of date from the oldest on the bottom. The boxes have the dispensing side that the milk bags can be pulled from. This only works for rectangle shaped bags obviously.

Two: They will defrost faster! With the frozen milk spread out, there is a larger surface area for warm water to touch if warming straight out of the freezer. If you have a solid chuck of milk, it will take much longer to penetrate the middle and thaw completely.

My mind was blown! It seemed so logical and practical but I honestly didn’t think of this. I had weeks and weeks worth of milk frozen in my fridge in blocks.

Why timing of pumped breast milk matters

In addition to writing the date and amount of milk in the bags, my doula suggested noting the time the breast milk was pumped.

Breast milk contains higher levels of certain hormones depending on the time of day. Cortisol levels in breast milk are highest in the morning, while tryptophan is highest in the evening. These aid in the awake and sleep patterns of babies.

When you match the timing of pumped milk to when you are feeding the bottle, the hormone levels will best match what your child should be getting at that time of day. Pretty cool stuff how precise our bodies are!

Feeding milk at the incorrect time of day can even be a cause of disrupted sleep patterns in some babies. No new mom wants that during an already sleep deprived time in our lives.

In conclusion…

I hope this information can help you be more confident about breast milk storage guidelines and preparation. If you have any special tips or additional info you would like to add, please leave a comment for the community below!

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