How to Store Breast Milk
Incorrect handling and storage of breast milk can lead to bacterial growth and spoilage, compromising its nutritional value and potentially affecting your baby’s health and wellbeing. Here you’ll learn how to store breast milk correctly.
Whether you’re a new mother looking to build a stash of stored breast milk, a working parent returning to work, or a care giver, this guide will provide practical tips and knowledge for safe and optimal breast milk storage. With the right preparation techniques and knowledge, parents can ensure the safety and quality of their baby’s breast milk, providing them with the best possible start in life.
Related: Pumping 101: A Beginner’s Guide
Key Takeaways
- Follow proper breast milk storage guidelines for freshness and safety.
- Different storage methods apply to fresh, refrigerated, and frozen milk.
- Temperature, container choice, and hygiene affect breast milk shelf life.
- Label and date all stored milk to use the oldest first.
Human Milk Storage Guidelines
The Centers for Disease Control and Prevention (CDC) provides essential guidelines for how long breast milk can be safely stored:
| Storage Method | Max Storage Time | Best Practices |
|---|---|---|
| Room Temperature (77°F/25°C) | Up to 4 hours | Keep away from heat, sunlight |
| Refrigerator (39°F/4°C) | Up to 4 days | Store in the back, not in the door |
| Freezer (0°F/-18°C) | 6–12 months | Use storage bags, leave space for expansion |
| Thawed Milk (previously frozen) | 1-2 hours at room temp, 24 hours in fridge | Do not refreeze |
Traveling with Breast Milk: If you’re flying, be aware of TSA regulations. Breast milk is considered a medically necessary liquid, meaning you can bring more than the usual liquid limit. Keep milk in clearly labeled storage bags or bottles, and inform security officers at checkpoints. If transporting frozen milk, pack it in an insulated cooler with dry ice or frozen gel packs to maintain its temperature.
Related: How to Create a Pumping Schedule
Factors That Affect Breast Milk Shelf Life
Breast milk is a valuable source of nutrition for infants, and proper storage is crucial to ensure it remains safe and nutritious for your baby. Several factors can affect the shelf life of breast milk, including temperature, sanitization, container choice, and freezer quality.
Storage Temperature
- Higher temperatures encourage bacterial growth and reduce milk freshness.
- Lower temperatures help maintain the milk’s nutrients and prevent spoilage.
- Always store milk in the back of the fridge or dedicated breast milk mini fridge where temperatures remain stable—avoid the fridge door.
Proper Sanitization
- Wash hands before expressing, handling, or storing breast milk to prevent contamination.
- Clean and sterilize pump parts and storage containers after each use.
- Use BPA-free storage bags or bottles specifically designed for breast milk preservation.
Freezer Quality
- Home Freezers: Keep at 0°F (-18°C) or lower for long-term storage.
- Deep Freezers for Breast Milk: Maintain at -4°F (-20°C) for the longest storage time, up to 12 months.
- Minimize temperature fluctuations—avoid opening the freezer frequently to maintain consistency.
- Preventing Freezer Burn: Squeeze out excess air from storage bags before sealing to reduce the risk of freezer burn and preserve milk quality.
Best Storage Containers for Breast Milk
When it comes to storing breast milk, there are two main options to choose from: milk storage bottles and milk storage bags. The choice of container will depend on how the milk will be stored, whether at room temperature, refrigerated, or frozen.
Breast Milk Storage Bottles
✔️ Reusable & durable
✔️ Easy to clean & sterilize
✔️ Compatible with most breast pumps for direct pumping
✔️ Provides better protection against leaks
❌ Takes up more space in the freezer
❌ Requires cleaning and sterilization after each use
Breast Milk Storage Bags
✔️ Space-saving, great for freezer storage
✔️ Pre-sterilized & disposable
✔️ Easier for portioning milk into smaller amounts
✔️ Can be laid flat for compact storage
❌ Can leak if not sealed properly
❌ Not as durable as bottles, may tear with rough handling
❌ Single-use, creating more waste
Related: How to Choose a Breast Pump
How to Store Breast Milk Properly
Before Expressing & Storing Milk
- Wash your hands thoroughly with soap and water before expressing or handling breast milk.
- Use clean and sterilized storage containers, such as BPA-free bottles or breast milk storage bags.
- Label each container with the date and volume of milk to ensure proper rotation and usage.
Filling & Sealing Storage Containers
- Leave some space at the top of storage containers to allow for expansion when freezing. Milk expands as it freezes, and overfilled containers may leak or burst.
- Ensure lids and seals are tightly secured to prevent contamination and spills.
- Store containers at the correct temperature based on when you plan to use the milk—room temperature for short-term, refrigeration for medium-term, and freezing for long-term storage.
How to Store Breast Milk Properly
Before Expressing & Storing Milk
- Wash your hands thoroughly with soap and water before expressing or handling breast milk.
- Use clean and sterilized storage containers, such as BPA-free bottles or breast milk storage bags.
- Label each container with the date and volume of milk to ensure proper rotation and usage.
Filling & Sealing Storage Containers
- Leave some space at the top of storage containers to allow for expansion when freezing. Milk expands as it freezes, and overfilled containers may leak or burst.
- Ensure lids and seals are tightly secured to prevent contamination and spills.
- Store containers at the correct temperature based on when you plan to use the milk—room temperature for short-term, refrigeration for medium-term, and freezing for long-term storage.
How to Thaw Breast Milk Safely (Best Methods & What to Avoid)
| Thawing Method | Time Required | Best Practices |
| Refrigerator | 12-24 hours | Best method, maintains milk quality |
| Warm Water Bath | 15-30 minutes | Place container in warm (not hot) water |
| Running Water | 5-10 minutes | Hold container under warm water |
| Bottle Warmer | Varies | Follow manufacturer’s instructions |
Avoid: Microwaving breast milk – It destroys nutrients and creates hot spots.
How to tell if breast milk is bad: Look for a sour smell, strange color, or separation that doesn’t mix after swirling. If in doubt, throw it out!
Frequently Asked Questions (FAQ)
1. Can fresh and frozen breast milk be mixed?
Yes, but only if they are the same temperature. Cool freshly pumped milk in the fridge before combining it with frozen milk.
2. How long can breast milk stay at room temperature?
Fresh milk is safe for up to 4 hours at room temperature (77°F/25°C or lower).
3. Can I store breast milk in the fridge in a bottle?
Yes! Use a clean, sterile, tightly sealed breast milk storage bottle or bag.
4. Can I put breast milk back in the fridge after my baby drinks from it?
No. Once a baby has fed from a bottle, discard any leftover milk within 2 hours to avoid bacterial contamination.
5. How can I store breast milk when traveling?
Use an insulated cooler with frozen ice packs to keep breast milk fresh for up to 24 hours. Refrigerate or freeze as soon as you arrive at your destination.
Final Thoughts on Breast Milk Storage & Safe Handling
Proper breast milk storage ensures your baby gets the freshest, safest milk possible. Follow temperature guidelines, use BPA-free storage containers, and label your milk properly. Whether you’re building a freezer stash or preparing bottles for daycare, these best practices will help keep your breast milk fresh and nutritious.
Still have questions about pumping and milk storage? Check out Pumping 101 for a full beginner’s guide or explore our in-depth breast pump reviews to find the best pump for your needs!
