Storing breast milk properly is crucial for preserving its nutrients and ensuring it is safe for your baby to drink. Many nursing mothers find that storing milk in bags is a convenient option, especially for building a reserve in the refrigerator or freezer. However, there are some guidelines to follow when storing breast milk in bags.
Quick Answer: Yes, you can store breast milk in bags in the fridge.
Breast milk storage bags designed specifically for human milk are considered safe for storing milk in the refrigerator for up to 4 days. It’s important to use breast milk storage bags rather than regular plastic bags. Here are some guidelines for proper storage:
- Make sure to wash your hands before expressing or handling breast milk.
- Pump milk into a clean container, then transfer into a clean milk storage bag designed for breast milk.
- Get as much air out of the bag as possible before sealing it.
- Label the bag with the date the milk was expressed.
- Store the bag in the back of the fridge, not the door.
- Use the oldest milk first when feeding to ensure nothing goes to waste.
- Throw out any unused milk after 4 days in the fridge.
Storing in bags takes up less space and thaws more quickly than rigid containers. However, be cautious of leakage. Use bags designed for breast milk that have a double zipper seal and are BPA-free.
Can any plastic bag be used to store breast milk?
No, regular plastic bags like sandwich bags or plastic grocery bags should not be used to store breast milk. Only use breast milk storage bags designed specifically for human milk storage. Here’s why:
- Regular plastic bags are too thin and may leak or spill.
- The material of regular bags isn’t approved for food storage.
- Regular bags contain chemicals like BPA that can leach into the milk.
- Milk storage bags are thicker, made of food-grade material, and have a double zipper seal.
- Storage bags designed for breast milk are sterilized and verified safe for human consumption.
Using regular plastic bags runs the risk of contamination, leakage, and potentially harmful chemicals. Investing in quality breast milk storage bags gives you peace of mind that you are safely storing your expressed milk.
How long can breast milk be stored in bags in the fridge?
According to the CDC and AAP, breast milk stored in bags in the refrigerator is good for:
- Up to 4 days if stored at 39°F or colder.
- Up to 3 days if stored between 39-59°F.
The cooler the temperature, the better for preserving nutrients and preventing bacterial growth. Storing milk toward the back of the fridge, not the door, helps keep it consistently cold.
Some additional fridge storage tips include:
- Store bags of milk toward the back, where temperature fluctuates less.
- Lay bags flat in the fridge so milk spreads out evenly in a thin layer.
- Put freshly pumped milk in the back, pushing older milk forward.
- Use the oldest milk first when feeding baby.
Monitor fridge temperature and toss any bags of unused milk after 4 days max. The time limits help avoid spoilage and maintain nutrition.
Room temperature storage
The timeline is much shorter if bags of pumped milk are left out at room temperature:
- Up to 4 hours is safe if the room is cooler than 77°F.
- Up to 2 hours if room temp is warmer than 77°F.
Bacteria grows rapidly if milk is left unrefrigerated over these time limits. Frozen milk left to thaw at room temp is still fine up to these time limits as well.
How to thaw breast milk stored in bags
To safely thaw bags of frozen breast milk:
- Refrigerator thawing: Move frozen bags to the fridge overnight, about 12-24 hours.
- Cold water thawing: Seal bags in a zip-top bag if needed to prevent leaks. Submerge in cold water, changing water every 30 minutes until thawed.
- Never thaw at room temperature or in hot water.
- Gently swirl bags midway through thawing to distribute milk evenly.
- Use thawed milk within 24 hours.
Microwaving can create hot spots that damage nutrients, so it is not recommended. Refrigerator thawing is ideal, but cold water works well for a quicker option. Use caution with bags as they can leak during warming.
How long does thawed breast milk last?
Previously frozen breast milk that has been thawed in the refrigerator or with cold water should be used within 24 hours. Here are some guidelines from the CDC and AAP on use of thawed milk:
- Use within 4 hours after fully thawed if kept at room temperature.
- Up to 24 hours after thawing if kept refrigerated.
- Discard any milk remaining after a feeding during the 24 hour window.
- Do not refreeze breast milk once thawed.
The 24 hour timeline helps avoid bacterial growth in milk that has been thawed. Make sure to label bags of frozen milk with the date pumped before freezing so you can follow the oldest-first order for feeding.
How to clean bags before pumping and storing
Properly cleaning and drying bags before use helps prevent contamination:
- Wash hands thoroughly before handling bags or pumping parts.
- Inspect bag seams and packaging for damage.
- Wash bags with hot, soapy water and rinse well.
- Air dry on a clean dish towel or paper towels.
- Alternatively, clean with a microwave steam bag sanitizer.
- Store cleaned bags in a clean space until use.
Cleaning bags just before you pump can help remove residue left from manufacturing. Never reuse bags, as they are designed for one use only. Follow your sanitizing directions whether washing by hand or using a sanitizing device.
Sanitizing bags
For extra assurance, you can sanitize storage bags just prior to use:
- Boil – Place bags in boiling water for 5 minutes.
- Steam – Use a microwave steam bag sanitizer.
- Bleach – Soak in a solution of 1 tablespoon bleach per gallon of water for 5 minutes.
- Vinegar – Soak in a solution of 1 part white vinegar to 3 parts water for 5 minutes.
- Dishwasher – Place on top rack of dishwasher and run a hot cycle.
Be sure to air dry or towel dry thoroughly after sanitizing. This extra step helps kill germs, but standard washing with soap and hot water is sufficient if bags are cleaned properly.
How to store bags of milk
To get the most storage space in your refrigerator or freezer, try these tips for storing bags:
- Lay bags flat to distribute milk evenly and take up less space.
- Use milk storage racks designed to hold bags upright.
- Put newly pumped bags toward the back of the refrigerator.
- Freeze bags laid flat in freezer bins or bags.
- Once frozen, bags can be stacked or stood upright for compact storage.
Being strategic with bag storage helps optimize fridge and freezer space. Always date bags when you fill them so you can follow a first-in, first-out system.
Avoiding spills and leaks
To prevent messy spills or leaks with bags:
- Make sure seals are fully closed on bags before freezing or storing.
- Store bags upright with seals flipped down in hard sided containers.
- Put bags in secondary hard containers like plastic bins while thawing or transporting.
- Place bags in sealed larger bags when freezing to prevent rips.
Double bagging or using hard containers provides an extra safeguard against leaks. Discard any bags that seem faulty or rip easily when full.
Does freezing breast milk in bags preserve nutrients?
Yes, freezing is an excellent way to preserve the majority of nutrients in expressed breast milk, including when using storage bags. According to research:
- No significant loss in macronutrients like fats, protein, and carbohydrates.
- Slight declines seen in some micronutrients like vitamin C and glutathione after freezing and thawing.
- Key antibodies like IgA remain stable, along with other immune components.
- No major impact shown on nutritional value of milk stored up to 6 months frozen.
Freezing is the best long-term storage method to retain breast milk integrity. Limiting freezer time to 6 months or less optimizes nutrition. Handle with care when thawing and warming to avoid excessive nutrient breakdown.
Avoiding nutrient loss
To help minimize nutrient loss when freezing breast milk:
- Freeze milk shortly after pumping, ideally within a day.
- Store bags toward the back of the freezer where temperature is most stable.
- Avoid storing bags in freezer doors where milk may be exposed to more air and temperature fluctuations.
- Thaw slowly in the refrigerator overnight whenever possible.
Safe storage practices help retain nutritional content. Research indicates freezing in bags has very good nutrient retention compared to other storage containers.
What are the signs of spoiled breast milk?
Check bags of refrigerated or thawed breast milk for the following signs of spoilage:
- Smells soapy, rancid, or rotten
- Changes texture and appears curdled or lumpy
- Pink, yellow, green, or grey tinge in color
- Has been stored over recommended time limits
When in doubt, remember the phrase “When in doubt, throw it out.” Do not feed spoiled milk to your baby. Discard any milk with signs of spoilage or expiration to avoid gastrointestinal upset.
Avoiding contamination
To help avoid spoilage and contamination:
- Wash hands and pump parts before collection and storage.
- Clean milk storage bags properly before each use.
- Use clean containers and bags designed specifically for breast milk.
- Ensure containers and seals have no cracks or damage.
- Promptly store milk in the fridge or freezer after pumping.
Following hygienic steps when pumping, collecting, and storing milk helps avoid bacteria or other contaminants that could lead to spoilage or illness.
Signs milk is still safe to feed
Here are signs bags of refrigerated or thawed breast milk are still safe to use:
- Appears creamy white or pale yellow in color
- Lacks any foul or strange odor
- Has been stored properly within recommended time limits
- Milk separates into layers but remixes smoothly when swirled
- Does not contain any clumps or lumps
Use your senses of sight and smell along with adhering to storage guidelines. When milk meets these criteria, it retains beneficial nutrients and antibodies to nourish your baby.
When in doubt, toss it out
If you have any doubts about the safety of a bag of stored milk:
- Err on the side of caution and discard the milk.
- Discard if you can’t remember when it was pumped.
- Toss milk that is borderline in terms of smell or appearance.
- Don’t taste milk to check if it’s spoiled.
Feeding spoiled milk can make your baby very sick. If bags are not clearly within safety guidelines for refrigerator or freezer storage, throw away the milk.
Conclusion
Storing breast milk in bags is a convenient option for many nursing mothers. Bags take up less space and thaw more quickly than rigid containers. However, proper usage guidelines should be followed to keep milk safe for your baby. Only use breast milk storage bags, not regular plastic bags. Limit fridge storage to 4 days maximum. Handle milk carefully when thawing and warming to preserve nutrients. With safe handling, breast milk stored in bags retains the majority of its nutritional properties and antibodies, making it an excellent way to provide your baby with the benefits of your milk even when you can’t nurse directly.
