Microwaves action on milk for infants

Kerry Dalley kerryd at atlantis.actrix.gen.nz
Sun Jan 15 04:52:20 EST 1995

In article <1995Jan11.120949.1 at hkpucc.polyu.edu.hk>,
 <bcdlee at hkpucc.polyu.edu.hk> wrote:
> In article <3ekm7b$ch1 at rc1.vub.ac.be>, scorteel at resulb.ulb.ac.be (Stephane Corteel) writes:
> > As a young father (my baby now is 7 weeks old) I read a lot...
> > I've read (and some people also told me) that warwing up a feeding
> > bottle using a microwave oven is not recommended because the microwaves
> > cause molecular changes in some proteins of the milk.
> > 
> > But, at this time, nobody could confirm that or give me an more
> > scientific explanation.
> > 
> > If someone could provide me a answer that an engineer like me can
> > accept, it would be very nice.
> > 
> > Thank you very much for any information
> Dear Stephane,
> You have raised a question that is of major concern. I am father of a 15 months 
> old daughter and a second one is coming in a couple of weeks. I have never dare 
> to use the microwave for warming up the milk. It causes uneven heating. 
> Microwave heating starts heating from the very inside of your food/drink. 
> The conventional boiling method heats from the outside inward. When taking care 
> of infants, patience is all you need. They don't died by being hungry for 10 or 
> 15 minutes.
> As to the molecular changes of proteins by microwave heating, conformational 
> changes must take place like other heating/denaturing processes. I am not sure 
> of the energy level carried by the microwave, but I think it is not high enough 
> to cause major changes at level of the atoms in the milk proteins. 
> If cannot spare the 10 - 15 minutes, microwaving can work. BUT, do mix the 
> bottle throughly after heating and then test the milk by puting a few drops on 
> the back of your hand.
> The routine we used is to keep a vase of cold boiled water and another vase of 
> boiled water kept at 95 (the electric water vase will do it), and prepare the 
> milk fresh every time. We are probably lucky, as our daughter has got the habit 
> of sleeping through the night when after two months old.
> Daniel Lee
> Hong Kong Polytechnic University
> > 

Just a reference I had here :-)


|ACCESSION NO:  92-93-0419
|       TITLE:  Microwaving Can Lower Breast Milk Benefits
|      AUTHOR:  RALOFF, J.
|     JOURNAL:  Science News
|    CITATION:  April 25, 1992, 141(17): 261.
|        YEAR:  1992
|    PUB TYPE:  Article
|    ABSTRACT:       Women who work outside the home can express and store
               breast milk for feedings when they are away. But parents and 
               caregivers should be careful how they rewarm this milk. A new 
               study shows that microwaving human milk--even at a low
               setting--can destroy some of its important disease-fighting
                    Breast milk can be refrigerated safely for a few days or 
               frozen for up to a month; however, studies have shown that 
               heating the milk well above body temperature--37 degrees C--
               can break down not only its antibodies to infectious agents, 
               but also its lysozymes, or bacteria-digesting enzymes.
               Neonatal nurses routinely thaw or reheat breast milk with 
               microwave ovens.
                    Pediatrician John Kerner, Jr. and his Stanford 
               University co-workers report finding that compared to
               unheated breast milk, microwaved milk lost lysozyme activity,
               lost antibodies, and fostered the growth of more potentially
               pathogenic bacteria. Milk heated at a high setting (72
               degrees  to 98 degrees  C) lost 96% of its lysozyme activity
               and 98% of its immunoglobulin-A antibodies, agents that fend 
               off invading microbes.
                    Surprisingly, the researchers also found some loss of 
               anti-infective properties in breast milk microwaved at a low 
               setting--and to a mean of just 33.5 degrees  C. Adverse
               changes at such low temperatures suggest microwaving itself 
               may in fact cause some injury to the milk above and beyond
               the heating.
                    But Randall Goldblum of the University of Texas Medical 
               Branch in Galveston disagrees, saying, "I don't see any
               compelling evidence that the microwaves did any harm. It was 
               the heating." Lysozyme and antibody degradation in the
               coolest samples may simply reflect the development of small 
               hot spots--potentially 60 degrees  C or above--during
               microwaving, notes Madeline Sigman-Grant, of Pennsylvania
               State University in University Park. And that is to be
               expected, she says, because microwave heating is inherently
               uneven--and quite unpredictable when volumes less than four 
               milliliters are involved, as they were in Kerner's study.
                    Goldblum considers use of a microwave to thaw milk an 
               especially bad idea, because it is likely to boil some of the 
               milk before all has even liquefied. Stanford University
               Medical Center no longer microwaves any breast milk, Kerner 
               notes. And that is appropriate, Sigman-Grant believes,
               because of the small volumes of milk that hospitals 
               typicallly serve newborns--especialy premature infants.

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