Pleonast is right–I know that when they’ve pasteurized breastmilk, they’ve found that it ruins some of its anti-infective properties.
And that’s an important point, actually–that breastmilk has its own, well, “disinfectant” in it. It’s true that it’s generally collected in anaseptic ways, but its cells can attack germs. It’s said (although just now I’m still looking for a cite) that breastmilk that has been collected in a container will have less bacteria after 15-30 minutes than it does when first tested.
For more info on the microwaving thing, better data might be found from source in Denmark and Sweden, because they maintain more breastmilk banks than the U.S. does and thus is more likely to have (and disseminate) hard info on how to heat breastmilk.
OK, folks, I did some actual medical research, and found that the warnings parroted on every web site and other source of consumer information are unjustifiably absolute.
The two really germaine articles I found are from 1992 and 1996, repectively, which shows there’s not mich scientific interest in the question. One (Quan et al) showed that there was little effect on anti-infective factors of microwaving in the 20-25 degree celsius range. (I think that’s between like 70 and 80 F, but check me.) They found some very bad effects but only when microwaving ro 98 celsius, which is close to boiling. I hope no one would do that in practice!
The other study (Ovesen et al) showed that thawing of milk as high as 60 degress celsius (way above body temp) did not affect the content of vitamins b1 and e or of linoleic or linolenic acids.
So, apparently, there’s not much reason not to carefully thaw out your breast milk from the freezer.
My first child was fine with fridge-temp milk, and many of the conventional-wisdom sites out there suggest that you need only take the chill off breast milk before feeding. I don’t trust them so much anymore, but if they’re right about this, then you can warm your milk to a pretty cold but thawed state in the microwave.
Refs:
The effect of microwave heating on vitamins B-1 and E, and linoleic and linolenic acids, and immunoglobulins in human milk
Ovesen L, Jakobsen J, Leth T, Reinholdt J
INTERNATIONAL JOURNAL OF FOOD SCIENCES AND NUTRITION
47 (5): 427-436 SEP 1996
EFFECTS OF MICROWAVE-RADIATION ON ANTIINFECTIVE FACTORS IN HUMAN-MILK
QUAN R, YANG C, RUBINSTEIN S, et al.
PEDIATRICS
89 (4): 667-669 Part 1 APR 1992
Based on the cites posted by Pleonast, freezing already kills the immunolical properties of breast milk. Based on nogginhead post, micorwaving breastmilk until warm doesnt harm the immunological properties.
Based on my personal experience (no, my wife gave me the milk, I only stored the excess and fed at night) I dont think it harmed my eldest any.
First, I only refrigerate expressed milk. Freezing takes too long to thaw properly.
Second, I put it in disposable bags meant for breastfeeding. I hate cleaning the bottles even though we did use them.
Third I microwave it for only 20-30 seconds. any more and steam comes out of the nipple and that aint good. I check half way to make sure its not too hot. If its not warm enuf after 30 seconds (dor whatever reason) i zap it 10 seconds more.
and finally, I shake the thing gently. I keep shaking the bottle while walking back to my baby. I do the old temperature on the wrist technique just before giving it to my baby. Taking a quick suck to check for temperature was deemed a no-no by the wife.
My child is 16 now and driving me batty with her teenage shennanigans. She’s in good health and is good enuf to be in honors class (when she puts her mind to it instead of her friends) she was a fat lil baby and now shes skinny and almost as tall as me and I am 5’10".
The real answer is that microwaves just add heat to something. The microwaves themselves don’t break down any molecules - it’s nonionizing energy, just like out of your cell phone, and the only way it can cause damage is to heat up something so much that the heat does it.
The only thing about microwaves is that they might heat things unevenly, so that although the milk as a whole might not be ready, there can be localized hot spots, which can be dangerous (plus the nutrients in that little hot spot might be lost).
However, if you microwave for short periods of time and then shake the bottle between, it works fine. It did for my two, anyway. I wouldn’t recommend thawing it from being frozen in this manner, because it takes so long that hot spots would be hard to avoid. With my kids, I’d let it thaw out ahead of time, and then nuke it up to serving temperature.
Just so noone thinks Mangetout is making things up, I heard the exact same thing, once… the source actually said this was the root of the ‘don’t microwave hysteria’. I am not having any luck finding a cite, though…
What the heck is a microwave heater anyway? Mines an oven. Like I said never more than 30 seconds for a 6 oz bottle.
Formula doesnt have any of immunological properties of breast milk and I have seen many babies thrive on that. This sound like a hysteria causing story. It presents a conclusion without supporting fact. The intensive care unit might have frozen the milk, over heated the milk, kept the milk out beyond its freshness limits, who knows. Expressed milk can be kept in room temperature for 10 hours and is warm enuf for a baby to use.
This doesn’t exactly support the story mangetout and Donovan heard, but the abstract (all I saw) from one of the two papers I cited does in fact refer to the fact that neonatal (or premie? Can’t recall) units do (or did) heat breast milk using microwave. They might even have used the phrase “microwave heater”. Maybe that’s what Baxter calls it so they can charge the hospital 10 times what you’d pay for your Sanyo at Target.
I still haven’t managed to get my mind around this. Do you mean that tea or coffe would taste different depending on how you warmed it? That goes entirely against everything I have ever thought of microwaves/thermodynamics. I can kind-of see that the microwaves might couple in a slightly different way with some more complex molecules, but wouldn’t the energy be absorbed by the water all around, before it can undergo any kond of molecular change?
Cite please! (Note, I’m not implying that I don’t believe you, just that I’d love to understand the mechanism.)