After you’ve finished pumping your breastmilk, you can maintain its many nutritional properties and avoid contamination by storing it in the proper containers. This liquid gold fuels your baby, so knowing how to keep it as safe as possible is super important. Let’s get into it!

You have options when it comes to storing your breastmilk — some good, some not so good.

Fridge and short-term freezer storage

⭐ Stainless steel containers

PROS: A great non-plastic alternative that is shatterproof and made with antibacterial materials.

CONS: Thinner stainless steel bottles do not do well in the freezer.

⭐ Glass containers

PROS: Good for fridge and freezer storage. Will not leach chemicals into your breastmilk. 

CONS: Not shatterproof and will break easily if dropped.

🚫 Plastic freezer bags

PROS: Affordable up front 

CONS: Expensive over time because you have to keep purchasing them. Disposable and wasteful, these single use bags end up in landfills. 

Long-term freezer storage

⭐ Silicone cubed containers (check out the Ceres Chill Milkstache trays!)

PROS: Freeze milk in perfect proportions for easy defrosting. Take up less space in the freezer than dozens of bags. Cubes can be transferred to silicone bags once fully frozen, and the cubed trays can continue to be filled when you’re ready to make more!

CONS: None!

⭐ Silicone bags

PROS: Easy to use, easy to clean and BPA-free, these are a great alternative to disposable bags.

CONS: Can be expensive to buy a lot if storing a large amount of milk

🚫 Plastic containers

PROS: Durable and usually the most affordable option. 

CONS: Some plastic storage containers leach chemicals like BPA (bisphenol A) and phthalates into breastmilk. While most companies now produce BPA-free breastmilk storage containers, there still isn’t enough research into the effects of other chemicals found in plastic.

When labeling breastmilk, write the date of expression on the container. If your baby goes to daycare, it might also be good to label the milk with their name.

It’s important to note that the composition of your breastmilk constantly changes to suit the needs of your baby. There are some special circumstances in which you might need to include extra information on your milk bags to know when to use them. 

For example, if you are breastfeeding and pumping and your baby comes down with a cold or a virus, it’s good to note that on your milk bags. The milk that you produce during this time could speed up their recovery.

You can also choose to include the time of day that the milk was collected. Levels of cortisol are three times higher in milk that was pumped in the morning versus milk that was pumped at night, while melatonin levels rise in the evening and peak at midnight. 

This means that our milk helps provide time-of-day information to our babies. Researchers suspect that “mistimed milk” might interfere with the development of a baby’s circadian rhythms, so if you feel that your baby is experiencing sleep troubles, try giving them the milk that was expressed at certain times of the day!

To avoid spills or messes, it’s important to be super careful when transferring breastmilk from your collection container into a different container.

When transferring your milk to bags, use a funnel if your bottle doesn’t have a narrow neck. If you’re pouring milk from the Ceres Chill Breastmilk Chiller outer chamber, be sure to keep your connector screwed on to give you a smaller opening and more control. 

If you’re transferring milk from bottle to bottle to combine for a fuller feed, using something like the bökee, a hands-free baby bottle holder that is great for keeping one bottle secure while you pour into another.

To keep your milk as safe and fresh as possible and avoid contamination, be sure to work the following tips into your routine:

• Wash your hands and pump parts before starting your session.
  
  
• Clean the pump parts in between sessions, either by using our portable washbasin bag, and pump wipes, or cleaning sprays. You can also use this fridge hack: store your pump parts in a gallon-size zip-top bag in the fridge and just wash them every few sessions. (It is important to note that this is not a CDC-approved method of keeping parts clean throughout the day.)
  
  
• Always be sure to thoroughly clean your parts. Only wash your pump parts with your other pumping gear in a separate container or washbasin. Don’t wash them in the sink with the rest of your dishes!
  
  
• Be sure to keep all storage containers clean and sealed.
  
  
• Store your milk at the correct temperature. 

Overall: Breastmilk is incredibly strong and can withstand a lot, but following these guidelines is really important to make sure that you’re giving your baby the safest milk you can. If you ever suspect that your milk has been contaminated or gone bad, do a taste and smell test to be sure. If it smells or tastes sour or ‘off’ in some way, you can still freeze that milk for future milk baths or topical uses!

• The Cleveland Clinic on milk storage
• 5 ways to prevent breastmilk contamination
• The Bokee Blog: Breastmilk collection and storage

In the fridge: Slowest but most preferred

This is the preferred way to thaw because it causes less fat loss compared to other thawing methods. Because the length of defrosting time depends on several different factors, it’s best to take the milk out of the freezer and put it in the fridge about 12-24 hours before you need it. Be sure to use that milk within 24 hours of it being completely thawed (meaning no more ice crystals). 

In a container of warm/lukewarm water: Best for immediate use

If you’re warming a bag for your baby to drink ASAP, thawing in a bowl of warm water is the quickest way to do it. Remember that once the milk has been warmed, it should be used within 2 hours, so it’s best to only use this method if you’re using the entire bag of milk. All you would do is fill a bowl with warm water and pop the bag in. Wait a few minutes for it to fully defrost, and then pour it into a bottle!

A great alternative to bags and wasted milk is our Milkstache, which allows you to freeze milk in perfect ½ ounce quantities. Instead of defrosting an entire bag and wasting extra milk if your baby doesn’t drink it all, you only need to defrost the exact amount you need. Check out this cool tutorial.

In a bowl of cold water: Best for using some now, and saving some for later

If you’ll only be using a portion of the milk in the bag right away, this is a great method to use. You can fill a bowl with cold water, add your milk in, and wait for it to thaw out. Once it’s thawed, you can store it in the fridge for prepping bottles later. Since all that milk will still be cold, it does not need to be used within two hours. This milk would be good for the next 24 hours, similar to the guidelines when defrosting in the fridge.

That's right, Ceres Chill's Breastmilk Chiller can also be used to warm milk. Here is the step-by-step process from our product guide:

• Defrosting breastmilk (Exclusive Pumping)

Ready to start bottle feeding your baby? It’s a learning process for both of you so here are some tips for introducing a bottle and setting your little one up for success. (Remember – while newborn babies commonly have 6-8 feeds every 24 hours and 8 - 12 feeds is the goal, there’s no set amount of food or number of feeds your baby SHOULD have, so just feed your baby when they are hungry.)

• When first introducing a bottle, be sure to pick a time when your baby is not too hungry or full. It’s easier to introduce new things when they're calm and comfortable. 
• Be sure to test the flow of the milk or formula from the bottle. It should be a steady drip, but not a flow. A slow flow nipple is preferred.
• Cuddle your baby close, in a sitting position, when feeding from the bottle.
• Position the bottle at a horizontal or parallel angle to the ground so that the milk only comes out when your baby sucks, letting the baby control the flow. 
• Offer them small amounts at first and let them take a break when it seems like they need one.
• Stop feeding from the bottle when your baby seems full, even if the bottle isn’t empty. Don’t force them to finish the bottle.

• Feed the baby when their cues indicate hunger, rather than on a schedule.
• When feeding, hold the baby in an upright position. It’s also best to hold a baby at other times than when being fed, so as not to train the baby that they must eat in order to be held.
• Switch from one side to the other midway through a feeding to provide for eye stimulation and to overcome a side preference.
• Feed the baby for 10-20 minutes at a time. Try to make appropriate quantities last that length of time. This allows the baby to recognize when they are full.
• Begin feeding by gently allowing the infant to draw the nipple into his mouth rather than pushing the nipple into the infant’s mouth.
• Stroke baby’s lips from top to bottom with the nipple to elicit a rooting response of a wide-open mouth and then allow the baby to ‘accept’ the nipple rather than poke it in.
• Consistent with a breastfed rhythm, the caregiver should encourage frequent pauses while the baby drinks from the bottle to mimic the breastfeeding mother’s let-down patterns. This discourages the baby from guzzling the bottle and can mitigate the nipple confusion or preference.
• Only feed the baby until the baby is full; don’t encourage the baby to finish a bottle. If the baby is dozing off and releasing the bottle nipple before the bottle is empty, that means the baby has had enough. Don’t reawaken the baby to finish it!

• Bottle-feeding (CDC)
• Giving the bottle (RaisingChildren.net)

There are legitimate clinical explanations for low milk supply, like breast or chest surgery, trauma to the chest or breast area, anatomical differences, or even hormonal or endocrinology disorder. These specific issues need to be assessed by a lactation consultant or IBCLC to determine if they are causing low milk supply so you can set and meet your breastfeeding goals. 

There are also many ways society judges milk production that are not true signs of low milk supply. Most women produce just the right amount of milk that their babies need. Unfortunately, a lot of women still believe they are not making enough thanks to the mistaken opinions of social media and well-meaning family and friends. 

Your body is uniquely wired to create breastmilk that targets the specific needs of your child. You’ve probably heard that one way to check your supply is to pump. While in theory this makes sense because you can “see” how much milk baby is getting, it’s not accurate for a number of reasons:

1. Baby’s mouth is designed specifically for breastfeeding, so they get more milk out than a plastic pump can. 
   
   
2. Since a pump removes milk differently than a baby does, our bodies sometimes have a harder time responding to the pump. In fact, some women don’t respond at all. For those women, they might get little to no milk out when they pump but are successfully able to exclusively feed from the breast for as long as they choose to breastfeed. 
   
   
3. You might see on social media posts from moms or parents who are pumping 10+ ounces at a time, while your output is much less than that when the average output in place of a nursing session is 2-3 ounces combined. Take those posts with a grain of salt! 
   
   
4. You were told by a well-meaning family member that babies should only eat every 4 hours and it seems like your baby is eating every hour, so that must mean your milk supply has gone down, right? No! Every woman has different milk storage capacity. Similar to how we all come in different sizes and shapes, so do our breasts. Some breasts might have smaller storage capacity and baby will need to feed more often. But rest assured, it is extremely normal and expected for your little one to breastfeed at least every 2-3 hours and then go through growth spurts and phases where they will eat more often. Those frequent feeds in a short amount of time are called clusterfeeding. Totally normal and good for your supply! 
   
   

Thanks to these common misperceptions, many women assume that they are “low producers” and start to make changes to produce more or supplement what the baby gets. Often women have misdiagnosed their production and take steps to remedy the situation, but these steps can lead to conditions that create low production, making it a self-fulfilling prophecy. Often, if there’s a dip in your supply, it is a temporary issue that your body will remedy on its own. 

If you are concerned about your milk supply, the best way to determine the reality of the situation is to contact a lactation consultant. While family, friends or even strangers on the internet may have advice about your milk production, they are unlikely to have specific training in lactation. Get the best advice you can from the best advisor you can and sleep easier. Your body is doing exactly what your baby needs!

• You are experiencing no pain with latching, and your nipples are not bleeding or cracked. 
• Baby is nursing at least 8-10 times in a 24-hour period, and nursing at least every 2-3 hours.  
• Baby is gaining weight on their own growth curve. 
• Baby is having at least 6 wet diapers in a 24-hour period. 
• Baby is meeting or exceeding their developmental milestones. 

Of course, if you or baby are having any issues with breastfeeding, please seek out a lactation consultant near you and talk to your pediatrician. 

Keeping our breastfeeding gear clean is important, but it can be super challenging and confusing when you’re away from home. We keep getting this same question: what exactly is “clean”? This question leads to follow-up questions like have I done “enough” to keep me and my baby healthy? Do I need to invest in a sterilizer or is soap and warm water enough? What is the “fridge hack”? Is it safe?

All of it can feel like…a lot. Some people’s idea of perfection is not easy to maintain when you're at work, traveling or even just trying to survive at home. But perfection is not necessary. This part of the process is manageable.

When cleaning your parts, you want to make sure to keep them separate from other dishes or non-breastfeeding items in the sink to prevent everything from getting dirtier with food, grease or bacteria. You may also want to use a special soap for baby items that is fragrance/dye free and can break up grease. Using a scrub brush that fits into pump part nooks and crannies and hasn’t been used to clean anything other than your baby bottles, nipple shields, flanges and tubing is a must. All of the other rules and extra stuff can be really overwhelming.  

So, what’s a mom to do? Don’t stress! We’ve got everything you need to know right here.

Sterilizing is making something free of bacteria and all living microorganisms. There are several ways to sterilize your pump parts:

• A steam/heat sterilizer — works to kill bacteria by exposing the parts to saturated steam under pressure. 
• A UV sterilizer — uses ultraviolet germicidal irradiation to break down certain chemical bonds that cause a microorganism to be unable to multiply.
• Cold sterilization — submerging your pump parts in a bucket of cold water with a sterilizing tablet or solution for
  30 minutes. 

Disinfecting is a bit different than completely sterilizing. While sterilizing destroys all microorganisms, disinfection/sanitizing eliminates or removes harmful microorganisms from inanimate objects and surfaces. You can disinfect your pump parts by boiling them in hot water for one to five minutes or using sanitizing sprays.

While this may already seem pretty overwhelming, there’s some good news: you don’t NEED to boil your pump parts every day or submerge them in a solution for 30 minutes. The most important thing is to make sure that your parts are clean and uncontaminated. 

Cleaning works by using soap and water to physically remove germs from surfaces. This process does not necessarily kill germs, but by removing them, it lowers their numbers and the risk of spreading infection.

To make sure that your parts are clean, inspect your entire kit to check for mold or old milk droplets before use — pump tubing can be extra tricky to clean, so if you notice that it’s moldy or soiled, it’s best to replace it.

After you pump, thoroughly washing your parts with warm water and soap in a washbasin is sufficient to keep everything clean on the daily. You can also clean your parts in the dishwasher if it's recommended by your pump manufacturer. Allow the parts to air-dry, and then you’re all set! 

You can also use cleaning wipes (like these amazing Bella B wipes) for a quick and easy cleaning!

For a healthy, full-term older baby, it is not necessary to fully sterilize your parts every day, but cleaning your parts every day is extremely important. 

The exception to this is if your baby is less than three months old, currently ill, or born prematurely. In that case, the CDC recommends that you sterilize all your breastfeeding gear at least once a day.

The CDC breast pump cleaning recommendations are as follows:

Before pumping, wash your hands thoroughly, inspect your pump kit and tubing to make sure that it’s clean, and clean (wipe down) your pumping area. After pumping …

• Disassemble your pump tubing and all parts that come in contact with your breast/breastmilk (flanges, valves, membranes, connectors and milk collection bottles)
• Rinse your pump kit to remove any remaining milk
• As soon as possible after use, clean all of the pump parts that were in contact with your breast/breastmilk. 

For cleaning by hand, the CDC recommends the same methods above - use a washbasin, add soap and water, scrub, rinse and dry, or place your parts in the dishwasher. After you’re done, clean your washbasin and bottle brush.

For extra germ removal, the CDC states that you can sanitize your pump kit by using a microwave or plug-in steam system, or by boiling them and allowing them to air-dry. 

The FDA states that while it’s not possible to sterilize pump parts at home, dishwashing soap and warm water will do just fine:

“All breast pump parts that come in contact with breast milk, such as bottles, valves and breast shields, should be cleaned after each use. It is not possible to completely sterilize breast pump parts at home, even if you boil them. However, sterilization is not necessary to keep these parts safe and sanitary. You can do that by thoroughly washing away germs and bacteria with liquid dishwashing soap and warm water.”

All of the parts do fit in sterilizers, but over time, the high heat and intensity can be hard on them and any of your breastfeeding gear. UV sterilizers can also affect the integrity of the plastic parts by breaking the bonds in them. 

The best way to clean all of your Chiller parts is to wash them with warm water and dish soap. Sanitizing wipes and cold sanitizing work perfectly for all Chiller parts as well. But there are options if you want to take extra steps.

Outer Chamber

You should always hand wash the outer chamber to keep it looking as beautiful as ever, but you can fill it with boiling water as another cleaning measure. 

Inner Chamber

The inner chamber can go right on the top rack of the dishwasher or be placed in boiling water. Immersing it in boiling water is not necessary per the FDA guidance, but it can be done if you want to take that extra step. We do not recommend actively boiling it for sustained periods. 

Plastic parts

It's best to avoid boiling the plastic parts - instead, they can go on the top rack of the dishwasher with the inner chamber! 

Try washbasin bags

Another option for disinfecting your pump parts, Chiller parts, baby bottles and more away from home: a portable, water-resistant washbasin like the All-You-Need Washbasin Bag. Before leaving for your trip or workday, the only prep needed is to fill the easy-squeeze soap dispenser with your favorite baby soap.

If you don’t have a convenient way to clean your pump parts on-the-go, you can choose to use the fridge hack — just pop your parts in a resealable bag like the boob bag) and stick them in the fridge between sessions! This works to ensure that the milk droplets on them don’t spoil and won’t be contaminated. Be sure to wash all of your parts thoroughly when you get home. This method is great for full-term babies — if you have a newborn/preemie baby, speak with your pediatrician or read up on the CDC guidelines for safe practices.

Cleaning your pump parts daily is essential for the health and well-being of your baby, but it is not necessary to completely sanitize your parts every day, unless your little one is less than 3 months old, born prematurely or currently ill. Using a separate washbasin with warm water and dish soap is perfect for everyday cleaning. 

Getting used to pumping and all the “rules” that come with it definitely takes some time, but we don’t have to over-complicate things for ourselves. With all of the above information, you’ll be able to pump and clean your parts with confidence. You got this, Mama!