I have a baby on the way and I am looking into bottle sterilizers. My concern is if they are really effective at disinfecting. Some claim to disinfect in as little as 5 minutes. I am not sure that is enough exposure time. I am also having a hard time finding actual specification as to what temperatures the sterilizer reaches. Any help would be greatly appreciated.
Sterilization using solely water or steam would indeed take more than five minutes. Steam that is just at 100°C would take close to an hour and a half to completely sterilize the vessels - and a better process is to repeat it several times (Tyndallization, referenced in that article as well).
However, you're not just using steam here; you're also washing the bottles in soapy water. You also don't have to get to the level of cleanliness that a clean room requires - here there is a misuse of the word "Sterilized". You want "sanitized". A couple of bacteria here or there won't be a disaster - you just need there to be not enough to cause the milk to go bad or make your baby sick. (You're probably not being sufficiently careful with the bottles post-sterilization, anyway.) Sanitizing means reducing the level of bacteria by 99.999%.
Boiling or steaming for 5-10 minutes is usually the recommended time. Restaurants sanitize their dishes in 85°C water for 15 minutes; as water gets hotter, it's more effective at sanitizing. Note that this is as a third step after washing and rinsing - just like restaurants - and does not remove any particulate objects.
If your baby has a medical condition that requires more care than that, please ask your doctor for the specifics. You can sterilize at home, either using chemical sterilization agents or steam, but it's much more involved than the bottle steamers that you're buying at Buy Buy Baby or whatnot.