Preferably, human milk should be refrigerated or chilled right after it is expressed. Acceptable guidelines for storing human milk are as follows:
At room temperature (19-26°C, 66-78°F,) for 4 hours (ideal), up to 8 hours (acceptable)
In refrigerator (4°C, 39°F) for 72 hours (ideal); up to 8 days (acceptable)
In freezer compartment of refrigerator with a separate door (-18°C, 0°F) for 3-6 months.
In deep freezer (-20°C, -4°F) for 6 months (ideal); up to 12 months (acceptable)