News Articles, Breastfeeding, Fetus/Newborn Infant, Health Briefs
How long should breast milk be stored in a freezer?
by Melissa Jenco, News Content Editor
Ahrabi, AF, et al. J Pediatr. July 13, 2016, http://bit.ly/2axTgG9.
Breast milk can be frozen for up to nine months without losing macronutrients, researchers found.
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The Academy recommends storing breast milk for three to six months if frozen in a deep freezer at 0 degrees
Fahrenheit (-18 degrees Celsius) or below. The Human Milk Banking Association of North America says milk
can be stored under such conditions for up to a year, although less than three months is preferred.
Researchers sought to determine how freezing breast milk affects pH, bacterial counts and nutrient contents.
They collected 100 milliliters of milk from 40 mothers. Some of the milk was frozen at -20 degrees Celsius for
one, three, six or nine months (fresh frozen), while other samples were refrigerated at 4 degrees Celsius for 72
hours then frozen at -20 degrees Celsius (refrigerated frozen). Both groups of milk were transferred to -80
degrees Celsius until analyzed, the same temperature as a baseline group.
Researchers found milk pH and gram-negative colony counts decreased over the nine months of frozen storage
regardless of prior refrigeration. Total bacteria and gram-positive colony counts also declined, most rapidly in the
refrigerated frozen milk.
The team noted the importance of "intestinal bacteria and its diversity."
"In this regard, prior refrigeration before freezer storage may accelerate these potentially deleterious effects on
milk microflora," they wrote.
Over time, the milk's concentration of non-esterified fatty acids increased, and there was no effect on total
protein, fat, lactoferrin, secretory IgA and osmolality.
"These data support current guidelines for freezer storage of human milk for up to nine months for both freshly
expressed and refrigerated milk," authors wrote.
Resources
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AAP policy "Breastfeeding and the Use of Human Milk"
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AAP breastfeeding website
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Information for parents on breastfeeding
Copyright © 2016 American Academy of Pediatrics