Cultures of Holder-Pasteurized Donor Human Milk After Use in a Neonatal Intensive Care Unit

Objective: Current guidelines state that human milk, once thawed, should be kept in a refrigerator for only 24 hours. We cultured Holder-pasteurized donor human milk (DHM) after thawing and refrigeration under clinical conditions. Study Design: Bottles of pasteurized DHM were thawed and used in a Regional Level 3 neonatal intensive care unit (NICU) in standard clinical fashion and kept refrigerated when not in use. Once no longer needed clinically, aliquots were cultured for bacteria. Results: In total, 30 bottles were returned for culture; six were excluded from analysis because human milk fortifier had been added, and two had been left out of the refrigerator. The remaining 22 bottles were culture-negative after having been thawed for 7-122 hours. Conclusions: DHM without additives was culture-negative for 24 hours or longer after thawing and routine NICU handling. These data indicate that unfortified Holder-pasteurized DHM handled appropriately and refrigerated remains sterile for 24 hours after thawing and perhaps longer. Further study is needed to confirm this.