I plan to go to an all day event 10am - 8pm and won't be able to sterilise bottles during the day. If I sterilise them in the morning, how long will I be able to use them for? If I put them in the fridge at the event, will they be considered sterile for longer? My baby will be 4 weeks old for this, if that makes a difference.
edit: to clarify, I am planning on taking empty bottles and filling them up from cartons when I am there. So I am talking about just the bottles, the milk is not a problem.