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editorial

Indian Pediatr 2012;49: 867-868

Fat Loss in Stored, Refrigerated/Thawed Expressed Breast Milk


KE Elizabeth

Professor of Pediatrics and Superintendent, SAT Hospital, Govt. Medical College, Thiruvananthapuram 695011.
Email: [email protected]
 


B
reastmilk is a life savior to millions of young children across the globe. Breast milk ensures physical, mental and emotional wellbeing. As per the ‘Infant and Young Child Feeding’ (IYCF) concepts, nutrition of the first 1000 days of life, which includes 9 months of intra uterine period (270 days) to 24 months post natal period (730 days), lays the foundation for the nutritional and health status of an individual. Nature has assigned the responsibility of this period solely on the mother. Among the IYCF practices, an important bottle neck is suboptimal breastfeeding due to various reasons including employment or other commitments of mothers. Expressed breast milk (EBM) being the mainstay in the feeding of preterm and low birth weight (LBW) babies and with several mothers going out for work, there is need for storing and thawing. As milk expands on freezing, the container should not be full during storage. EBM should be stored in clean, capped glass or hard polypropylene plastic containers or special freezing bags.EBM should not be stored in the door and in disposable bottles or feeding bottles or plastic bags designed for general household use. Before expressing or handling breast milk, hands should be washed with soap and water. Fresh breast milk is always superior as storage and thawing decreases fat, certain vitamins, cellular and host defense properties of the milk. Fat can adhere to plastic container and tubing, and cellular components to glass. At room temperature, fat is broken down to triglycerides which change the pH of milk and turn it sour. This is different from the problem of bacterial contamination. Actually, the bacteria will be less in number at six hours than they were at the time of pumping because of the protective qualities in the milk, which suppress bacterial growth. On the other hand, the enzymes decline later and bacterial counts also start to rise [1].

For thawing frozen EBM, it should be placed in the refrigerator the night before, followed by gentle rewarming of the container in a bowl of warm water or holding under warm running water [2]. Heating and microwaving are not recommended due to uneven heating and loss of anti-infective properties. Milk separates during storage and fat rises to the top. Do not refreeze milk once it has been thawed or partially thawed. It is prudent to note that thawed breast milk should be used within 24 hours and any remaining milk should be discarded. Some mothers have a high level of lipase enzyme and their milk may smell and taste soapy when thawed. This milk is not harmful, but the baby may sometimes refuse it.

Freezing, storing and thawing are known to result in loss of fat, and thereby energy [3]. Even in fresh breast milk, the lactose and protein content remain relatively constant, but a variation is noted in the fat content. Thawing of frozen breast milk results in separation of fat and a decrease in bile salt dependent lipase, vitamins C, B6 and folacin, that are heat labile [4]. Pasteurization (62.5 ºC × 30 min) does not alter fatty acid composition of milk, but sterilization (120 ºC × 30 min) results in up to 13% fat loss and also linoleic and arachidonic acid [5]. At the melting point of fat, solid fat turns to oil fat and oil can adhere to the sides of the container. In the comparative study of milk using fresh milk (FM) and thawed frozen milk by way of overnight refrigeration (RM) and warming in warm water (WM), the authors have reported that RM retains better fat content than WM [6].

The information that thawing frozen breast milk by leaving it in refrigerator compartment the night before is a better method to preserve quality and energy than warming by placing in warm water needs to be passed on ‘from the bench to bedside’, as refrigerators are now an integral part of all households.

Funding: None; Competing interests: None stated.

References

1. Hamosh M, Ellis LA, Pollock DR, Henderson TR, Hamosh P. Breast feeding and other working mothers: effect of time and temperature of short term storage on proteolysis, lipolysis and bacterial growth in milk. Pediatrics. 1996;97:492-8.

2. American Academy of Pediatrics. Breast feeding. In: Kleinmann RE, editor. Pediatric nutrition handbook. 6th ed. Elk Grove Village: American Academy of Pediatrics. 2009. P.51-60.

3. Berkow SE, Freed LM, Hamosh M, Bitman J, Wood DL, Happ B et al. Lipases and lipids in human milk; effect of freeze- thawing and storage. Pediatr Res. 1984;18: 1257-62.

4. Lavine M, Clark RM. Changing pattern of FFA in breastmilk during storage. J Pediatr Gastroenterol Nutr. 1987;6:769-74.

5. Fidler N, Sauerwald TU, Koletzko B, Demmelmair H. Effects of human milk pasteurization and sterilization on available fat content and fatty acid composition. J Pediatr Gastroenterol Nutr. 1998;132:876-8.

6. Thatrimontrichai A, Janjindamai W, Puwanant M. Fat loss in thawed breast milk: Comparison between refrigerator and warm water. Indian Pediatr. 2012;49:877-80 .

 

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