Storage Systems for Milk Bags

A storage system comprising:

• a. a plurality of shelves;
• and
• b. a housing with collapsible side walls such that the walls are extendable such that the housing fits within a first freezer space that has a first height dimension and such that the walls are compressible to fit within a second freezer space that has a second height dimension smaller than the first height dimension of the first freezer space, and wherein the housing is configured to receive one or more of the plurality of shelves to form one or more compartments, wherein each compartment is configured to store a storage bag.