Human milk can be stored
at room temperature (66-72°F, 19-22°C) for up to 10 hours
in a refrigerator (32-39°F, 0-4°C) for up to 8 days
in a freezer compartment inside a refrigerator (variable Tª due to the door opening frequently) for up to 2 weeks
in a freezer compartment with a separate door (variable Tª due to the door opening frequently) for up to 3 to 4 months.
in a separate deep freeze (0°F, -19°C) for up to 6 months or longer.
http://www.llli.org/FAQ/milkstorage.html

In these artistic representations, the Virgin has so much milk that the assessment to the public inspectors of the Church (Virgin of the Milk) or to the souls of the Purgatory (Virgin of the Suffrage) .Actually the mother needs to know how to preserve her milk since this way she can prolong the lactation of her son. For it, will express the milk with a hand or electrical pump.