Follow CDC Proper Storage and Preparation of Breast Milk recommendations. Store your milk in a personal insulated cooler bag with your name clearly labeled. You are welcomed to store your cooler bag in office break room refrigerators. If you do not have access to a refrigerator, your milk is safe in an insulated cooler bag with frozen-ice packs for up to 24 hours. Pick-up a free insulated cooler bag here: http://tiny.ucsf.edu/lactationsupplies