title: Alterations in the host defense properties of human milk following prolonged storage or pasteurization.
abstract: OBJECTIVE
  Preterm infants are often fed pasteurized donor milk or mother's milk that has been stored frozen for up to 4 weeks. Our objectives were to assess the impact of pasteurization or prolonged storage at -20 degrees C on the immunologic components of human milk and the capability of the different forms of human milk to support bacterial proliferation.
  
  
  METHODS
  The concentrations and activities of major host defense proteins in the whey fractions of mother's milk stored for 4 weeks at -20 degrees C or pasteurized human donor milk were compared with freshly expressed human milk. Proliferation of bacteria incubated in the 3 forms of human milk was assessed.
  
  
  RESULTS
  Relative to freshly expressed human milk, the concentrations of lysozyme, lactoferrin, lactoperoxidase, and secretory immunoglobulin A were reduced 50% to 82% in pasteurized donor milk and the activities of lysozyme and lactoperoxidase were 74% to 88% lower (P < 0.01). Proliferation of bacterial pathogens in pasteurized donor milk was enhanced 1.8- to 4.6-fold compared with fresh or frozen human milk (P < 0.01).
  
  
  CONCLUSIONS
  The immunomodulatory proteins in human milk are reduced by pasteurization and, to a lesser extent, by frozen storage, resulting in decreased antibacterial capability. Stringent procedure to minimize bacterial contamination is essential during handling of pasteurized milk.
authors.affiliation: Division of Pulmonary Biology and Neonatology, Cincinnati Children's Hospital Medical Center,Cincinnati, OH, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Akinbi
authors.forename: Jareen
authors.initials: J
authors.lastname: Meinzen-Derr
authors.forename: Christine
authors.initials: C
authors.lastname: Auer
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Derek
authors.initials: D
authors.lastname: Pullum
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kusano
authors.forename: Krzysztof J
authors.initials: KJ
authors.lastname: Reszka
authors.forename: Kira
authors.initials: K
authors.lastname: Zimmerly
mesh_terms: D000328:Adult; D005260:Female; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007155:Immunologic Factors / Q000032:analysis / Q000378:metabolism*; D007781:Lactoferrin / Q000032:analysis; D007784:Lactoperoxidase / Q000032:analysis / Q000378:metabolism; D008894:Milk Proteins / Q000032:analysis / Q000378:metabolism*; D008895:Milk, Human / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology; D009113:Muramidase / Q000032:analysis / Q000378:metabolism; D013242:Sterilization / Q000379:methods*; D055815:Young Adult
chemical_list: D007070:Immunoglobulin A; D007155:Immunologic Factors; D008894:Milk Proteins; D007784:Lactoperoxidase; D009113:Muramidase; D007781:Lactoferrin