Lansinoh’s Breastmilk Storage Bags have been specially designed so that they can be stored either in the fridge or freezer. These medical-grade bags have been manufactured without using any plasticisers, so there is no chance of any harmful substances getting into your breast milk.nThese storage bags have been pre-sterilised and are completely leak proof with a double zip for a secure seal. They feature an easy pour design and there is also a convenient tab on which you can write ‘use by’ dates.