First-time moms-to-be have numerous concerns about their baby’s health and they often wonder about all of the “what ifs.”
One query at the top of the list is, “Can you reheat breast milk more than once?” To answer your question: no, you can’t. You can heat leftover breast milk but only once. You must not reheat breast milk twice or thrice, and the leftover breast milk should be dumped within two hours of using it.
This is because the leftover milk gets contaminated in the baby’s mouth. It loses its essential nutrients, and harmful bacteria grow if it isn’t properly stored. Since the answer involves a lot of factors to consider, we have explained them in detail below. Keep reading!
Baby Formula Shortage & Breast Milk
Many moms switch their babies to formula instead of breast milk. This is usually an option availed for working moms and those who have some kind of problem with breastfeeding. Although it is entirely the mother’s decision to either breastfeed or look for alternatives, there are numerous research-backed benefits of breastfeeding your babies.
Unfortunately, formula shortages are becoming a major problem for parents whose babies depend on it to satisfy their nutritional needs. As an increasing population has found support in formula, many babies who are actually in need of formula are being deprived of it.
To overcome this problem, breast milk storage banks have been opened throughout the United States to accommodate babies who do not have access to formula or human milk. Mothers with high milk supply store pumped milk and send it to expressed breast milk banks. Sharing unused breast milk has helped millions of babies get the nutritional value they have been lacking. Precious liquid gold doesn’t get wasted either!
How Should You Store Breastmilk?
If you are a working mom who needs to pump and store breast milk for your baby, or you just prefer pumping over breastfeeding, you might wonder if your milk will lose its nutritional value and get spoiled if it’s stored for too long. To soothe your qualms, we have curated research-supported answers.
Typically, breastmilk can be used for up to six months if kept in ideal conditions. However, these conditions are not always available. Milk may be kept in the following conditions, but for varying amounts of time.
- Room Temperature: Freshly expressed milk can be kept at room temperature for up to four hours at a temperature of around 77 degrees Fahrenheit. Although it can technically remain at room temperature for up to six hours, it’s best if you dispose of it after four hours, especially when the room temperature is a little warm.
- Refrigerate: You can use expressed breast milk for up to four days if you refrigerate it immediately after pumping.
- Insulated Cooler: Unused breast milk can be saved for a whole day if kept in an insulated cooler.
- Deep Freezer: Breast milk can be stored in a deep freezer under clean conditions for up to twelve months, but using it within six months is best for the baby.
Keep in mind that the longer unused breast milk is stored, the more it will lose nutrients. Older breast milk has the least amount of vitamin C and is the least beneficial for the baby.
Safety Precautions for Breast Milk
There are additional tips you should follow to keep your baby’s milk safe from becoming a breeding ground for harmful bacteria.
- Always use storage bags that are specifically designed for breast milk. Alternatively, you may use food-grade containers.
- Air-tight lids on glass or plastic containers are necessary. Under no circumstances should you use cheap plastic bags or disposable bottles. They are not meant for storing breast milk and can ultimately harm your baby.
- The use of containers with recycling symbol 7 are dangerous to babies as they contain BPA.
Once you have successfully expressed breast milk, you need to be certain to abide by the following guidelines when putting the milk in the freezer.
- If you are certain that you do not want to use the milk right away, it is vital that you immediately put it in the freezer. This will keep the milk fresh, and the quality will be maintained.
- Label the dates on the bottle of breast milk, so you know how many days are left until expiry. Add your baby’s name, as well, if you hand over your baby to a babysitter.
- Don’t store bottles of breast milk in the refrigerator or freezer door. Storing it in the back of the refrigerator will ensure that the temperature stays constant and there won’t be a chance for the frozen breast milk to thaw out.
- Always leave an inch of breast milk at the top of the bottle or container as it tends to expand when frozen.
- Only store two to four ounces of expressed breast milk or as much your baby drinks in one session. This will help save your liquid gold to the last drop, and you will not have to throw it away.
- Do not tighten the lid of the bottle until it has frozen.
- If you are traveling, you can keep expressed breast milk in a cooler between ice packs. This will keep the milk fresh for twenty-four hours. Remember to transfer it to a refrigerator or freezer as soon as you reach your destination.
How Can I Make My Breast Milk Last Longer?

All those mommies who are wondering if they can use their breast milk for later use, rejoice! You can save your precious liquid gold for later use so your baby can get the essential nutrients only breast milk can provide. We have listed a few ways on how you can use safely store breast milk:
- If you want to store the remaining milk left by the baby, it can be left for two to four hours at ambient temperature. Leaving the milk out for too long could cause an initial bacterial load to travel through the baby’s mouth.
- Breast milk is easily and safely stored in the refrigerator. According to storage guidelines, you can store it for up to four days in the refrigerator.
- For a healthy baby, you must strictly check and balance the fridge’s cleanliness. Make sure to set the baby bottle near the back of the fridge, so it stays cold, and the constant opening and closing of fridge doors will not interfere with the milk’s temperature.
- If you are considering storing your breast milk for later use, you can do so by storing it in the deep freezer. This milk can be used for up to twelve months. However, it is advised by medical staff that you use breast milk within six months.
Thawing Breast Milk
Now you may be wondering about how to defrost milk. We will be covering the top three ways here.
1. Defrost Breast Milk In Refrigerator
Safe thawing in the refrigerator takes around twelve hours. If you know that you’ll need milk the next day, just place the bottle or container of breast milk in the refrigerator overnight. The milk needs to be used within 24 hours; it cannot be frozen again and must be thrown away.
2. Thaw Milk In A Bowl Of Warm Water
If you are in a hurry and want to defrost milk for the baby rapidly, this is the option for you. It barely takes twenty minutes. Fill a bowl of warm water and place the bottle or container of breast milk inside. Make sure that the lid isn’t submerged in the water so that water doesn’t enter the bottle.
Once the water is cooled, replace it with more lukewarm water (not hot water). Continue doing this until your milk is no longer frozen.
You can either give it directly to the baby or heat it first; your baby will let you know what he prefers. It is okay to feed cold milk to the baby as reheated breast milk loses its good bacteria and nutritional value.
3. Thaw Milk In Bottle Warmers
This is a very easy method for thawing and heating your breast milk. Take out the frozen milk and place the bottle in the bottle warmer. Once warmed, feed it to your baby. This is a good option as bottle warmers warm the milk to a certain temperature.
Here’s a fun fact: babies prefer body temperature milk as it feels just like milk straight from the breast.
Never heat breast milk in the microwave. When milk is heated in the microwave, it heats up unevenly, which creates hot spots in the liquid. This is dangerous for the baby and could lead to burns.
Can I Put Breast Milk Back in Fridge After Baby Drinks From It?
Many moms are concerned about whether they can put leftover milk in the fridge and reheat breast milk later, or if they should go down the safer road and throw it all away. To be honest, it is based on your better judgment, but according to the experts, there are a few options you can choose from.
Once your baby has finished feeding from the bottle, you can leave it at room temperature (around 77 degrees Fahrenheit). This milk should be used within one to two hours maximum. After this time, the bacteria in the milk will have grown considerably, and it is no longer safe to give your child.
When your baby leaves milk unfinished, you can put it in the fridge. This milk should be used within two hours. You do not need warm breast milk either; it can be drunk cold.
Can You Reuse Breast Milk After It Has Been Warmed Up?
Another concern new moms dwell upon is whether you can use breast milk once it has already been heated. The answer is yes. You can use reheated breast milk.
You must be cautious about one thing. Once you have warmed previously frozen milk or room temperature milk and fed it to the baby, you can, under no circumstances, put the bottle back in the refrigerator. It has to be thrown away. This is because the bacteria start to grow more rapidly once the breast milk has been heated.
Can You Put Breast Milk Back in Fridge After Warming?
Once the breast milk has been warmed, it cannot be put back in the fridge. The remaining bacteria grows swiftly once the milk has been warmed. It becomes unusable once it’s heated.
Breast Milk Wrap Up
You must feel like a lot of information is being thrown at you as a new parent, but it’s all for the sake of your baby. There are several factors to evaluate when considering reheating breast milk and reusing it.
Do keep in mind that unused breast milk differs from used breast milk as freshly expressed milk is free from all bacteria, whereas used has harmful bacteria transferred from the baby’s mouth.
Breastfeeding is certainly a wonderful gift from God. Enjoy feeding your baby and keep these bits in mind.