Pumped breast milk is a convenient way for nursing mothers to provide breast milk for their babies when they are unable to nurse directly. However, there is some debate over whether pumped milk needs to be refrigerated right away or if it can safely sit out at room temperature for a period of time. This article will examine the evidence and provide guidelines for safely handling and storing pumped breast milk.
Can pumped breast milk sit out at room temperature?
According to the Centers for Disease Control and Prevention (CDC), freshly expressed breast milk can safely sit at room temperature for up to 4 hours. After that, it is recommended to store the milk in the refrigerator or freezer.
The Academy of Breastfeeding Medicine agrees that pumped milk can be left out for 4-6 hours at temperatures up to 77°F. Once breast milk warms to room temperature, bacteria can start to grow rapidly. Refrigeration helps slow this bacterial growth.
So if you are going to use the pumped milk within 4 hours, it is generally safe to leave it out at room temperature. But if it will be longer than 4 hours before use, it is important to get that milk into the fridge as soon as possible.
Why does breast milk need to be refrigerated?
Breast milk needs to be refrigerated to restrict bacterial growth. Breast milk is the ideal food for babies – it contains proteins, fats, vitamins, minerals, digestive enzymes and antibodies. However, just like any food, it can also contain harmful bacteria. Refrigeration helps suppress bacterial growth.
Here are some key reasons to refrigerate pumped breast milk right away:
- Slows bacteria growth – Refrigeration reduces the growth of bacteria in the milk. Leaving milk out for an extended time allows more rapid bacterial multiplication.
- Avoid spoilage – Breast milk can spoil if left unrefrigerated, particularly in warm environments. Refrigeration preserves the nutrients and quality.
- Food safety – Refrigerating the milk reduces foodborne illness risks for the baby.
Proper refrigeration provides pumped breast milk the same shelf life and safety as milk directly from the breast. Following safe storage guidelines ensures the milk maintains maximum nutrients for your baby.
How long can pumped breast milk be left out?
Most experts consider 4 hours to be the maximum time pumped breast milk can safely sit at room temperature before it needs to be chilled. Here are some general time limit guidelines:
- Up to 4 hours – Freshly pumped milk can sit out at room temperature up to 4 hours.
- 4-6 hours – Some sources indicate it may be safe for up to 6 hours if the temperature is cooler (up to 77°F).
- Over 6 hours – After more than 6 hours at room temperature, it is best to discard the milk.
Keep in mind these time frames are for very clean conditions. Here are some other factors that can affect how long milk can safely sit out:
- Environment – Warmer environments can increase bacterial growth. Aim for under 77°F.
- Air exposure – Lids and covers help protect against contaminants in the air.
- Pump cleanliness – A thoroughly washed pump/parts reduces bacteria presence.
- Hand washing – Clean hands when collecting and handling breast milk.
Use lesser time frames if pumping or collecting milk in less clean conditions. When in doubt, earlier refrigeration is safest.
Can you add freshly pumped milk to already cooled milk?
It is best not to mix warm freshly pumped milk with milk that is already chilled in the refrigerator. The temperature change can impact the milk quality. Milk that is re-warmed after cooling tends to separate into layers.
According to La Leche League International, it is advised to cool newly pumped milk in the refrigerator before adding it to already cooled milk. For storage purposes, follow the time limits for whichever milk was least recently pumped.
Tips for handling pumped breast milk
Here are some best practices for safe handling and storage of expressed breast milk:
- Wash hands and equipment before pumping.
- Use clean bottles or storage bags made for breast milk.
- Label milk with date it was pumped.
- Seal containers tightly and place immediately in refrigerator.
- If transporting, use cooler/ice packs to keep cool.
- Aim to use cooled milk within 3-5 days.
- Frozen milk can generally be stored 3-6 months in freezer.
- Thaw frozen milk gradually in refrigerator or by swirling in warm water.
- Avoid reheating pumped milk more than once.
How to store refrigerated breast milk
Proper refrigerated storage preserves breast milk and keeps it safe for baby. Here are some refrigerator storage guidelines from the CDC and other experts:
- Temperature – Keep refrigerator at or below 39°F.
- Location – Store milk toward back of main body of refrigerator (not door).
- Duration – Refrigerated milk is good for up to 4 days. Freeze any excess supply.
- Containers – Use sealed bottles or bags designed for breast milk storage.
- Avoid cross-contamination – Store breast milk on a separate shelf above raw foods like meat.
Breast milk that is stored following these refrigeration guidelines can generally last 3-5 days if going to be used within that timeframe. Always smell the milk before using to check for any souring.
Does breast milk need to be refrigerated at night?
Breast milk that is pumped during night feedings still needs refrigeration. Night milk should not be left out on a nightstand or counter overnight.
The rule of 4 hours sitting out at room temperature applies to milk expressed at any time of day. So if pumped at 2 AM, it still needs refrigeration by 6 AM.
To avoid unnecessary disruptions for mom and baby at night, some tips include:
- Keep a mini fridge in the bedroom for overnight pumping sessions.
- Immediately store night milk in a cooler with ice packs.
- Take milk to kitchen fridge as soon as reasonably possible in morning.
Leaving milk out overnight can allow more bacterial growth leading to increased food safety risks for baby. Refrigerating nighttime pumped milk keeps it safe and usable for future feedings.
Does breast milk need to be refrigerated for daycare?
Breast milk that is pumped to be sent to daycare absolutely needs refrigeration. Daycares typically have guidelines requiring all bottles and milk to be chilled.
Here are some tips for handling breast milk for daycare:
- Refrigerate milk immediately after pumping.
- Transport milk to daycare in an insulated cooler bag with ice/freeze packs.
- Include labels on milk with child’s name and pumping date.
- Communicate milk storage guidelines with daycare provider.
Providing chilled breast milk for daycare feedings ensures it stays safe and nutritious for baby throughout the day. Open bottles that are unrefrigerated for over an hour should be discarded.
Can breast milk be left out while feeding?
It is generally fine for a baby to leave a bottle of breast milk unrefrigerated during the course of one feeding. However, there are some guidelines to follow:
- Feed breast milk immediately once warmed up.
- Always use a clean bottle and nipple.
- Do not allow baby to feed directly from storage bag.
- Throw away any leftovers not consumed within 1-2 hours.
Allowing a feeding baby to pause and return to the bottle helps reduce waste. But milk should not just be left sitting out at room temperature for extended times. Unfinished milk from a feeding should be discarded within 1-2 hours.
Can breast milk be left out after warming up?
Previously refrigerated or frozen breast milk can be warmed up for feeding. But it is best not to leave warmed up milk out unrefrigerated for more than 1-2 hours.
The optimal time frame is to warm what is needed for one feeding and use immediately. General guidelines include:
- Only warm up amount needed for current feed.
- Use warm water bath or bottle warmer.
- Swirl gently and test temperature before feeding.
- Feed immediately once warmed.
- Discard any excess within 1-2 hours.
Warming up refrigerated breast milk does not “reset” the clock. The milk should not sit out warmed any longer than refrigerated. Using warmed-up milk right away provides baby the freshest, healthiest milk possible.
Does breast milk need to be covered when refrigerated?
It is not necessary to cover or seal bottles of pumped breast milk being refrigerated or frozen. The refrigerator environment itself helps prevent contaminants from getting into the milk.
Here are refrigeration storage recommendations from the CDC:
- Store milk toward back of main refrigerator area.
- Use clean containers meant for breast milk storage.
- Leave space around containers for air circulation.
If transporting milk or storing where other people may access the refrigerator, lids or seals may be preferred. But in general, covering is not needed for milk refrigerating at home.
Can you mix refrigerated and frozen breast milk?
It is best not to mix milk that is freshly pumped with frozen milk. The thawed frozen milk may contain some separation or condensation.
Guidelines for combining refrigerated and frozen breast milk:
- Refrigerate fresh milk first before mixing batches.
- Let frozen milk thaw gradually overnight in fridge before mixing.
- Swirl gently to evenly distribute any separated milk fat, but do not shake vigorously.
Once different batches of milk are combined in the refrigerator, use within the guideline time limit for chilled breast milk (generally 3-5 days).
Does breast milk need to be refrigerated for a sitter?
Leaving pumped breast milk out for a babysitter or sitter should be handled the same as for any feeding. The milk needs to be chilled.
Here are some tips for providing breast milk for a sitter:
- Leave chilled bottles of breast milk ready in refrigerator.
- Include simple heating instructions for the sitter.
- Label milk clearly for the intended child.
- Instruct sitter to only warm what is needed per feeding.
Providing chilled, labeled bottles helps the sitter easily identify the milk and serve it fresh for each feeding. Only refrigerated milk should be left out for the sitter.
Does pumped breast milk need to be refrigerated for occasional use?
Even if pumped breast milk will only be used occasionally, it still requires refrigeration within the usual guidelines. Leaving pumped milk out can allow bacteria growth.
Typical storage guidelines indicate breast milk is good for:
- Up to 4 hours at room temperature.
- Up to 4 days refrigerated.
- Up to 6 months frozen.
These same storage times apply whether the milk is used daily or only occasionally. Date all milk so oldest milk can be used first. Follow safe refrigerated storage procedures, even for occasional use.
Can breast milk be left out to combine for storage?
It is best not to leave pumped breast milk out at room temperature in order to combine and store milk from multiple pumping sessions. Previously chilled milk should remain refrigerated.
Guidelines for combining milk:
- Refrigerate milk from each session as soon as possible after pumping.
- Keep milk chilled until ready to combine batches.
- Add freshly pumped milk to already chilled milk.
Combining refrigerated milk helps maintain proper temperature control. Milk that is left out too long before combining risks increased bacteria growth. Prioritize quick chilling over batching.
Does breast milk need to be refrigerated at work?
Pumped breast milk absolutely needs refrigeration at work. Leaving milk out all day will lead to increased bacteria growth and spoilage.
Here are some tips for handling breast milk while working away from your baby:
- Refrigerate milk shortly after pumping.
- Use workplace refrigerator or personal cooler pack.
- Label milk clearly with name and date.
- Transport home chilled in cooler bag.
Communicating with your employer about milk storage needs helps ensure you can refrigerate during the workday. Refrigeration preserves milk safety and quality.
Does breast milk need to be refrigerated for occasional caregivers?
Expressed breast milk left for occasional caregivers like grandparents or siblings should still always be kept refrigerated. Leaving milk out can lead to increased bacteria growth.
Tips for providing refrigerated breast milk for other caregivers:
- Chill milk promptly after pumping, per usual guidelines.
- Label milk clearly for the intended child.
- List date milk was pumped on the bottle.
- Communicate safe storage guidelines.
Even if a caregiver is only giving an occasional bottle, properly refrigerated milk is crucial. Follow the same pumping and refrigeration best practices.
Should breast milk be refrigerated at night if feeding on demand?
For moms who are breastfeeding on demand around the clock, pumping and refrigerating milk overnight is not necessary.
Guidelines indicate:
- Fresh milk direct from the breast is fine for night feeds.
- No need to pump and chill milk if nursing frequently at night.
- Any pumped milk should still be refrigerated within 4 hours.
If you tend to nurse more often overnight, that freshly sucked milk is optimal for baby. But occasional pumped milk still requires refrigeration within the usual timeline.
Conclusion
In most cases, it is recommended to refrigerate expressed breast milk within 4 hours. Rapid chilling helps restrict bacteria growth and keep milk safe and nutritious. Refrigeration preserves breast milk quality and freshness.
There are some exceptions where milk may be left out up to 6 hours, such as cooler environments or very clean collection conditions. But when in doubt, earlier refrigeration of pumped milk is best.
Following proper pumping and storage guidelines provides babies with the healthiest possible breast milk while allowing nursing mothers flexibility. Even when used occasionally, pumped breast milk still requires diligent refrigeration within the advised time limits.
