Stability of lactoferrin in stored human milk

OBJECTIVE: Lactoferrin from human milk (HM) provides antimicrobial and anti-inflammatory action in the neonatal intestine. HM-fed, critically ill neonates often receive previously frozen milk. Freezing is known to have deleterious effects on proteins. The aim of this study was to determine the effect of low temperature storage of HM on the concentration of lactoferrin. STUDY DESIGN: HM samples were collected and stored for different periods of time and at different temperatures per Centers for Disease Control and Prevention recommendations. Lactoferrin concentrations following freezing were compared with that in fresh HM. RESULT: Lactoferrin concentrations in refrigerated HM samples were stable for 5 days. After 3 months at -18 to -20C, the average decrease was 37%. Following storage for 6 months at -20 degrees C, lactoferrin decreased to 46%. CONCLUSION: Five-day refrigeration of HM does not appreciably decrease lactoferrin levels. Freezing HM for 3 months or more significantly lowers lactoferrin levels. There may be a role for occasionally providing fresh HM to critically ill neonates.