Where should you store your milk?  What container should your milk be stored in? What temperature should milk be stored at?  How long can milk be stored for? Knowing these answers will promote good milk storage habits that properly preserve your milk.

A Deeper Look:

Once you have finished your pumping session you’ll need to decide where to store the milk you pumped unless you plan to feed it to your baby within the next few hours.  Where you should store your milk will depend on how quickly you plan to feed it to your baby and whether you have access to a fridge or freezer.  Regardless of where you plan to store your milk, you should date it immediately even if the method is only temporary (ex. masking tape with the date on bottles).

Any suggested milk storage times discussed in this post are based on the use of very clean pumping equipment and milk containers.  Further, the following guidelines are for healthy, full-term babies.  If your baby is hospitalized or has a weaker immune system, click here.

For more information on cleaning your pump equipment, click here.  
For more information on when to replace pump parts, click here.  

For healthy, full-term babies, the CDC recommends the following:

(Table detailing breast milk storage guidelines)

Using a Cooler

If you are pumping outside of the home and will not have access to a fridge, you will want to plan to store your milk in a cooler.  Although the CDC does not provide guidelines pertaining to storing milk in a cooler, the La Leche League suggests that milk can be stored in a cooler (at a temperature of 5-39˚ Fahrenheit/-15-4˚ Celsius) for 24 hours with ice packs in constant contact with the milk containers and limited opening of the cooler bag.

Storing in the Fridge

Obviously, storing milk in the fridge is the easiest, most convenient option—you do not have to prep a cooler and the milk only needs to be warmed rather than thawed and warmed.  Refrigerated milk also has less fat loss and more antibacterial properties than frozen milk.  However, frozen milk still contains the nutritional properties babies need, so if you do not plan to use the freshly pumped milk within four days, you will want to freeze it.  For more information on storing milk in the freezer, click here.  However, regardless of whether you are storing milk in the fridge or freezer, place the milk in the back of the unit where it is coldest and the temperature is most consistent.  

If you are storing the milk in your fridge, you have many different methods to choose from.  For example, you may decide to store the milk:

• in the bottle you pumped into 
• using the pitcher method
• in a bag designed for feeding (such as the Kiinde Twist Pouch)
• in a silicone bag (such as a Zip Top Breast Milk bag)

The Pitcher Method

The pitcher method is a term used to describe the method of collecting pumped milk from an entire day’s pumping sessions into one large container and then using that milk to prepare the next day’s bottles.  If you plan to use this storage method, remember freshly pumped milk should be chilled in the fridge first—you should only add chilled milk to chilled milk.  If you prepare bottles for the next day ahead of time, and often have an oversupply, this method allows you to easily see if you need to freeze any milk at the end of each day, ensuring your milk is frozen at its freshest.  This storage method also saves space in your fridge!  Additionally, if you only store milk from a single day’s pumps in the pitcher and prepare bottles for the next day and freeze the leftover, you may not need to worry about dating each batch of milk stored in your fridge (of course date what you froze!).  Make sure your pitcher is made of glass or food-grade plastic (once source suggests looking for the number 5 recycling symbol and/or the letters PP on the bottom of the container) and can hold the total amount of ounces you pump in a day.  This method may be especially helpful in the early days of pumping when your supply has not regulated and your baby’s milk intake is fluctuating.

First In First Out Rule

Regardless of where you store the milk, use the “first in, first out rule” and feed the oldest milk to your baby first.  As it sits, breast milk naturally separates into a milk layer and a cream top when stored.  A gentle swirl should mix the breast milk back together.  If your milk smells rotten or tastes sour—toss it. Unspoiled milk should swirl evenly; if it doesn’t swirl evenly or has chunks, toss it. 

Smelling and Tasting Your Milk

If your milk has a soapy smell or taste, it may be an indication you have high levels of lipase enzyme activity.  If you do, not to worry, your milk is safe for consumption!  For more information on excess lipase activity and a method for preventing the change in smell and taste, click here.

Dating Your Milk

If you combine milk from different dates, the “new” date for the batch of milk is the oldest date of milk pumped. Milk should be the same temperature when combined, so freshly pumped breast milk should be chilled before adding it to milk already stored in the fridge

The EP&Me Take:

From the beginning, my Little did not latch well, so I began storing milk while at the hospital immediately following her birth.  At this point, I was only producing colostrum, which had to be hand expressed and stored in small syringes in the fridge.  Once my milk came in, everything changed and became more complicated—I began using a breast pump, and I needed to decide how to store the extra milk that my Little was not ready to consume.  

The Kiinde Twist Pouch

I was constantly washing pump parts and what felt like millions of teeny tiny bottle parts.  It was exhausting, and I needed something to change.  Enter the Kiinde Twist Pouch.  This milk storage bag changed my pumping life and allowed me to claw back some of the extra time that naturally disappears as a result of EPing.

The Kiinde Twist Pouch allows you to pump, store, warm, and feed in the same bag.  Kiinde has created a variety of adaptors that are compatible with many battery/rechargeable/electric non-wearable pump systems to allow many different users to use the Kiinde system regardless of their pump preference.  Once you are done pumping, you can screw the cap on, add the date on the side, and store in either the fridge or freezer.  When you are ready to warm the milk, you can place the bag directly into a bottle warmer and then pop it into the bag holder, squeeze the milk to the top of the bag (to remove excess air), push the nipple on, and start feeding.  My favorite part of using the twist pouch is that I only had to clean the nipple and give the bottle holder a light wash here and there.  And did I mention the bags are recyclable?  It was so freeing to not have to clean so many bottle parts, especially once we started daycare and multiple bottles would come home at the end of the day.

How I Used the Kiinde Twist Pouches

When I first started pumping and while I was still pumping frequently, I did not always pump into the Kiinde bags because I was not filling them enough.  If I knew I would pump about three ounces from each breast in one session, then I would pump into a Kiinde bag on each breast.  Otherwise, I would pump into one Kiinde bag and one bottle and then transfer the milk from the bottle to the bag once I was done pumping.  The bags can stand upright on their own and are incredibly easy to pour into and pour from.  I found comfort and peace in keeping track of the exact amount of milk I pumped each day, so at the end of each pump session, before combining the milk, I would separately weigh each bag or the bottle and bag using a kitchen scale and record the amount pumped for each side in a phone app.  Then I would combine the milk into the bag, date it (there is a specific spot on the side that I found easy to write on even when the bag was full) and pop it into the fridge.  At the end of each day, I would redistribute the milk—I referred to myself during this time as a “Mad Scientist” because I was pouring between many bags of milk and measuring, measuring, measuring!—into 4.5 ounce bags, which was the amount my Little wanted to consume in one feeding.  I often reviewed the milk counting what my Little was likely to consume in the next few days and would freeze milk that I didn’t think she would consume before it spoiled.  Sometimes the milk I froze was fresh milk, other times it milk that had been in the fridge for three days.  As long as it still smelled and tasted fine, it was fine to freeze for later.

Pro Tip 1: if you are pouring into a container and are worried about spilling, use your breast flange as a funnel (the two-piece flanges work best for this)

Pro Tip 2: if you are going to be sending milk bags into daycare, I suggest writing your child’s name on them while the bag is empty.  Once the milk is chilled, the condensation makes it extremely hard to write on the front of the bag with a Sharpie without causing the Sharpie ink to stop flowing.  Of course you do not have to use the Sharpie brand, but be sure that the ink you use is waterproof.

Storage in the Fridge

I stored the bags in long narrow plastic bins in the fridge and constantly reshuffled the milk to make sure the freshest milk was in the back and the oldest milk at the front and easily accessible.

Storage Times

We adhered pretty closely to the CDC guideline that fresh milk stored on the counter should be consumed within four hours.  However, other sources suggest 6 or even 8 hours is acceptable.  If it is a hot day, or the temperature in your environment is high, I would personally be more cautious about disregarding the CDC guidelines.  Similarly, although the CDC guidelines for consumption of milk stored in the fridge is within four days of expressing, other sources suggest milk may be safe to consume for up to 8 days if it was collected in a very clean way and stored in the back of the fridge.  I think we fed our Little milk that was 5 days old a handful of times, but I was careful to never go beyond day five because I did not want to risk throwing out milk that I had worked so hard for!  But in my situation, the milk on day 5 smelled and tasted fine to me and swirled evenly as discussed above, so I felt comfortable feeding it to my Little.

When our Little did not consume all of her milk at a feeding, we did feed it to her over the next 2-3 hours.  Sometimes we put it back in the fridge (some sources say this is fine to do and use at the next feeding), like when she fell asleep after starting a bottle, other times, when she was a bit older, we kept it out for an hour or two, which I do not think anyone recommends, but there were no issues that we were aware of.

The last thing I want to mention is that many breast milk supplies—such as milk storage bags and replacement breast pump parts—are covered by insurance or considered an eligible item for FSA/HSA accounts, so make sure you check what your insurance covers and whether it’s an eligible item.

Good luck safely storing all that liquid gold mama!