After cleaning and fully drying your breast pump parts, store them reassembled inside a clean, sealable food storage bag or a dedicated pump parts container. The key rule: parts must be completely dry before they go into any enclosed space, because trapped moisture is what allows bacteria and mold to grow. Getting from “just finished pumping” to “safely stored” involves a few specific steps, and the details matter most for babies under two months, premature infants, or those with weakened immune systems.
Clean Before You Store
Storage starts with cleaning. As soon as possible after each pumping session, rinse every part that touched breast milk under running water, then wash with warm water and dish soap. Even if you used hygienic wipes between sessions, the FDA says those wipes don’t replace a full soap-and-water wash before parts are used again or put away.
For babies under two months old, add a daily sanitizing step: boil the parts for five minutes, run them through a dishwasher cycle with a sanitize setting, or use a microwave steam bag designed for pump parts. Once daily is the recommended frequency. For older, healthy babies, standard soap-and-water cleaning after every session is sufficient.
Why Drying Matters More Than You Think
After washing, set all parts on a clean, unused dish towel or paper towel and let them air-dry completely. Don’t use a cloth towel to rub them dry, since towels can transfer bacteria back onto clean surfaces. The reason this step is non-negotiable: bacteria like Cronobacter sakazakii, which can cause serious illness in young infants, survive well on surfaces including bottles, pump parts, and countertops. Cronobacter can enter your home on shoes or hands and colonize damp kitchen surfaces. Putting parts away while they’re still wet creates exactly the kind of environment where these organisms thrive.
If you’re in a rush, placing parts on a clean drying rack with good airflow speeds things up. Just make sure no water droplets remain in flanges, valves, or connectors before you seal anything into a bag or container.
Best Containers for Storage
You have two main options for storing dry, clean pump parts:
- Sealable food storage bags. A fresh zip-top bag works well. The CDC specifically recommends an unused bag each time, which keeps outside dust, pet hair, and kitchen contaminants off your parts.
- Dedicated pump parts containers. Reusable containers made from BPA-free, phthalate-free polypropylene give you a more sustainable option. These are dishwasher safe and keep parts organized better than a loose bag tossed into a pump tote. Look for food-safe materials and a secure lid.
Whichever you choose, store the sealed container or bag in a clean, protected area. A closed cabinet or the inside of your pump bag both work. Avoid leaving parts out on countertops where they can pick up environmental bacteria.
The Refrigerator Hack: What to Know
You’ve probably heard the “fridge hack,” where you place unwashed pump parts in a sealed bag in the refrigerator between sessions instead of washing every time. The idea is that cold temperatures slow bacterial growth enough to make it safe to reuse parts without cleaning for several hours.
The CDC does not recommend this method. Their concern is that bacteria on refrigerated parts could still grow and contaminate the next batch of milk. That said, no real-world cases of infant illness have been documented from using this shortcut with healthy, full-term babies. The risk is theoretical rather than proven.
For premature infants, babies under two months, or immunocompromised babies, the fridge hack is not worth the gamble. For healthy older infants, many parents and lactation professionals consider it a reasonable trade-off that makes pumping sustainable, especially during long workdays. If you use it, keep parts sealed and refrigerated for no longer than the stretch between pumping sessions, and still do a full wash with soap and water at least once every 24 hours.
Storing Pump Parts at Work
Workplace pumping introduces a real logistical challenge: you may not have easy access to a sink, or the only sink is in a shared kitchen. The CDC offers several practical workarounds:
- Bring multiple pump kits. Use a fresh, pre-cleaned set for each session and wash everything at home that evening. This eliminates the need to clean at work entirely.
- Use microwave steam bags. If your workplace has a microwave, rinse your parts and then sanitize them in a steam bag between sessions. Check your pump manufacturer’s instructions first, since some parts (particularly certain valve types) shouldn’t be microwaved.
- Take used parts home. Seal them in a bag, keep them in a cooler or insulated pouch, and wash them all at once when you get home.
If you’re commuting, an insulated cooler bag with an ice pack keeps both expressed milk and used parts cold during transit. Store used parts in a separate sealed bag from your milk to avoid cross-contamination.
How Long Parts Stay Clean in Storage
There’s no official expiration window for how long properly cleaned and dried parts remain “clean” in a sealed bag. Practically, if parts were fully washed, fully dried, and sealed in a clean container or bag, they should be fine to use at your next session, whether that’s in a few hours or the next day. If parts have been sitting for several days without use, give them another wash before pumping. Dust and ambient bacteria can still accumulate over time, even in sealed containers, especially if the seal isn’t airtight.
Silicone valves, membranes, and duckbill valves deserve extra attention during storage. These small, flexible parts are easy to lose and tend to trap moisture in folds and crevices. Shake out excess water, confirm they’re dry to the touch, and store them with your other parts rather than loose in a bag where they can get crushed or contaminated.