Hi Barbara, thanks for your question. This can be a tricky subject with many possible areas of confusion: how long can you keep milk stored in refrigerator? Freezer? Can you re-freeze? What type of containers are best? Below, you will find a link to the answers to all of these questions. Regarding your specific question: freshly pumped breast milk can remain at room temperature for 4-6 hours before it needs to be refrigerated. Research shows that bacteria does not grow well in fresh human milk, so you don’t need to worry if you can’t rush it to the refrigerator right after you pump. It does make sense, however, to get it refrigerated or frozen as soon as possible, and to keep it cool while transporting it.
Any milk that is left over after a feeding can be saved for the next feeding (just a few hours), otherwise you should discard it. The reason is that bacteria from the baby’s mouth might have entered the bottle during feeding. This can lead to contamination if it sits too long.Click here for our full discussion on breast milk storage. The section that covers your question is at the very bottom of the page.
Dr. Jim