Fresh breast milk, when expressed under clean conditions, can be used safely up to four hours at room temperature, and for 24 to 48 hours when refrigerated immediately after expression. When frozen immediately, breast milk can last up to three months. In general, the freezer compartment of a household refrigerator is adequate for safe freezing. Although freezing breast milk does preserve most of the milk's nutritional value, some of the immunological, or disease-fighting, components of milk are inactivated by freezing. No studies have been done to determine whether babies who drink fresh breast milk exclusively get fewer colds or diarrhea illnesses than babies who get frozen milk occasionally. The health benefits of breastfeeding are so important that a nursing mother should not hesitate to feed her baby frozen, defrosted breast milk during temporary separations.