Effects of Refrigeration on the Bactericidal Activity of Human Milk: A Preliminary Study

J Pediatr Gastroenterol Nutr. 2007 Aug;45(2):275-7. doi: 10.1097/MPG.0b013e31805de507.


This study analyzed the bactericidal activity of human milk and how it is influenced by refrigerated storage. Nine samples of mature human milk were collected and divided into 3 aliquots. One was analyzed immediately, and the other 2 were refrigerated at 4 degrees C to 6 degrees C for 48 and 72 hours, respectively. All of the fresh samples exhibited bactericidal activity with an average value of 83.47% +/- 18.37%. Refrigeration for 48 hours did not cause significant modifications, whereas storage beyond 72 hours significantly lowered the degree of bacteriolysis versus fresh milk. In conclusion, human milk possesses bactericidal activity that remains stable during the first 48 hours of refrigerated storage, but it is significantly reduced beyond 72 hours.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Escherichia coli / drug effects
  • Food Handling / methods*
  • Humans
  • Milk, Human / microbiology*
  • Postpartum Period
  • Refrigeration* / adverse effects
  • Time Factors


  • Anti-Bacterial Agents