How to Clean and Sterilize Baby Bottles
Pediatricians used to advise sterilizing bottles and parts for the first 6 weeks, which often led parents to buying steam sterilizers. This is now generally considered unnecessary, since washing in the dishwasher is likely to be hot enough to thoroughly remove any germs. (If you would like to be extra cautious, you can place bottles and parts in a big pot of boiling water for a few minutes – this is a good step for brand new bottles and pacifiers).
For everyday cleaning of small bottle parts (i.e. nipples and rings), you can either wash in the dishwasher or by hand. I typically avoid washing anything plastic in the dishwasher, but make an exception for bottle parts. That’s because the rings do not come into contact with milk, and the nipples are silicon, which should be able to withstand the heat of a dishwasher. To keep the parts together, a dishwasher basket specifically made for bottle parts can be helpful.
To sterilize bottle parts in the early newborn phase, I placed the clean nipples and rings in a pyrex glass bowl and poured over boiling water, then drained after a few minutes.