Is microwave heating of water harmful?

Warming up breast milk: why not in the microwave?

The claim that baby milk heated in the microwave would develop risky protein changes has been scientifically refuted. For reasons of hygiene, infant formula must be freshly prepared for each meal. However, if baby formula is prepared in advance, the microwave can be used to warm the milk stored in the refrigerator (+ 4 ° C). However, it is essential to note: The contents of the warmed milk bottles can be heated to different degrees within the bottle. The wall of the bottle is only slightly heated in the microwave. It is therefore not possible to draw conclusions about the milk temperature from the outside temperature of the bottle. What feels at the right temperature on the outside could be too hot for babies on the inside.

The bottle should therefore be shaken carefully after it has been heated up in the microwave and the milk temperature should be checked by tasting it immediately before feeding. However, microwave ovens are not suitable for warming breast milk! In the laboratory at temperatures between 20 and 50 ° C, heating of breast milk in the microwave resulted in significant reductions in lysozyme and secretory IgA. The bactericidal effectiveness of breast milk was massively reduced at temperatures as low as 20 to 25 ° C. When warming breast milk, electrical bottle warmers with circulating air or so-called baby food warmers should be used. With these, the temperature of the water bath can be set precisely, but before feeding the bottle should always be shaken well and the temperature of the milk checked by tasting it beforehand. Incidentally, breast milk can separate into an aqueous and a fatty phase when you stand for a long time: the creamed fat is redistributed by carefully swirling (do not shake!).