We travelled with our babies in Thailand and Indonesia - those babies are now 13 and 10!!! - but when they were tiny babies I would sterilise their bottles using boiling water and "Milton" tablets.
The "Milton" tablets were berocca-type tablets that dissolved in water, and I bought them from a supermarket at home (Western Australia).
I also took bottles of Dettol along and used that in their bath water, and to also run a quick cloth over the hotel floors when they were crawling.
Overkill??? Probably!! But they never got sick while we were travelling

....so something worked!