Pumping at Work: How the Guidance Says to Store Your Milk

Returning to work while breastfeeding involves storing milk safely. The CDC says expressed breast milk is a food, and that you may store it alongside other foods in any refrigerator appropriate for food storage. ¹ Below is what the CDC and the Office on Women's Health say about how long it keeps, how to cool it on the way home, and how to keep pump parts clean - each point quoted and linked.

Key takeaways

• The CDC says expressed breast milk is a food and can be stored in any refrigerator appropriate for food storage. ¹
• The CDC says freshly pumped milk keeps at room temperature (77°F or colder) for up to 4 hours, in the refrigerator for up to 4 days, and in the freezer about 6 months is best, up to 12 months acceptable. ^{2 2 2}
• The CDC says you can carry freshly expressed milk in an insulated cooler bag with frozen ice packs for up to 24 hours. ¹
• The CDC says to always label breast milk containers with your name and the date you expressed the milk. ¹

**A quick, honest note:** we're not medical professionals - everything here was researched by us from the public sources listed at the bottom of this page, and it isn't professional advice. Read our full note ↓

How do I store breast milk at work?

The CDC says expressed breast milk is a food, and that you may store it alongside other foods in any refrigerator appropriate for food storage. ¹ For what to keep it in, the Office on Women's Health says to use breast milk storage bags made for freezing human milk, or clean glass or hard BPA-free plastic bottles with tight-fitting lids. ³ It adds a caution: do not use containers with the recycle number 7, which may contain BPA, and do not use disposable bottle liners or other plastic bags to store breast milk. ³

How long can pumped milk stay out?

The CDC gives windows for each place. It says freshly expressed or pumped milk can be stored at room temperature (77°F or colder) for up to 4 hours, ² in the refrigerator for up to 4 days, ² and in the freezer for about 6 months is best, with up to 12 months acceptable. ² The CDC frames these as general guidelines, and says various factors - milk volume, room temperature at expression, temperature fluctuations, and cleanliness - can affect how long human milk can be stored safely. ²

Can I use a cooler bag on the way home?

Within a limit the CDC sets. It says you can store and carry freshly expressed milk in an insulated cooler bag with frozen ice packs for up to 24 hours. ¹ The CDC adds what to do next: once you get home, use the milk right away, store it in the refrigerator, or freeze it. ¹

How should I label and clean?

The CDC gives two housekeeping points. On labelling, it says to always label breast milk containers with your name and the date you expressed the milk. ¹ On hygiene, the CDC says that it and most breast pump manufacturers recommend cleaning pump parts after every use to help protect babies from germs. ¹

Frequently asked questions

Can I keep my milk in the work fridge?

The CDC says expressed breast milk is a food and may be stored alongside other foods in any refrigerator appropriate for food storage. ¹

How long does pumped milk last in the fridge?

The CDC says up to 4 days in the refrigerator. ²

How long is a cooler bag okay for?

The CDC says up to 24 hours in an insulated cooler bag with frozen ice packs. ¹

How often should I clean pump parts?

The CDC says it and most pump manufacturers recommend cleaning pump parts after every use. ¹

A note from us

We're the team behind Yael & Michal. We are not doctors, nurses, lactation consultants, or psychologists, and nothing here is professional advice.

Everything above was researched by us from public, reputable sources - we name and link every one of them below - and summarized as carefully as we could, as a free resource for other mothers. We do this because we wished something like it had existed for us.

When we name an organisation such as the CDC, the NHS, La Leche League, or the Israeli Ministry of Health, we are only citing their published guidance; it does not mean they endorse, sponsor, approve, or are affiliated with us. They have no involvement with this site, and we never use their logos or seals.

Yael & Michal sells nursing bras, which are comfort garments and not medical devices; we do not claim they prevent, treat, or cure any medical condition. The health information here is written for you as a free resource - it is separate from anything we sell.

We try hard to get it right, and we cite our sources so you can check us. But we are not a medical authority, and this cannot replace talking to a professional who knows you and your baby. Please check anything that matters with your doctor, midwife, or an IBCLC lactation consultant. This content has not been reviewed by a medical professional. Reading this site does not create a doctor-patient relationship, or any other professional relationship, between you and us.

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Sources

1. Centers for Disease Control and Prevention (CDC). https://www.cdc.gov/infant-toddler-nutrition/breastfeeding/returning-to-your-workplace.html (retrieved 2026-07-10).
2. Centers for Disease Control and Prevention (CDC). https://www.cdc.gov/breastfeeding/breast-milk-preparation-and-storage/handling-breastmilk.html (retrieved 2026-07-10).
3. Office on Women's Health, U.S. Department of Health and Human Services (womenshealth.gov). https://womenshealth.gov/breastfeeding/pumping-and-storing-breastmilk (retrieved 2026-07-10).