The breast-milk can stay fresh for up to 4 hours at normal room temperature (23-26 degrees). You can store breast-milk for up to 3 days in the fridge. Label the bottles with the date and time, so you can use the oldest one first. Lastly, it can be stored in deep freezer for up to two weeks. You can also refer to this link for some useful guide on collecting and storing breast-milk -- http://www.medelabreastfeedingus.com/tips-and-solutions/11/collection-and-storage-of-breastmilk
Room temperature – Freshly expressed milk can be kept at room temperature for up to 4 hours. Refrigerator – Breast milk can be kept at the back of the fridge for up to 4 days. If you’re not going to use refrigerated breast milk within 4 days of pumping, freeze it right after pumping. You can read more here: https://sg.theasianparent.com/how-to-warm-breast-milk-from-fridge
Up to 4h in room temp and 3d in refrigerator