I was told the same thing - aparently they don't even sterilize bottlefeeding equipment in hospitals anymore. I'm breastfeeding and have a breast pump and a collection of bottles, and I bought a sterlizer so that I can use periodically. I do it everyone once in a while and I don't worry about storing them so they stay sterile (which they only do for 24 hours).

The midwife said to me (and i've heard it other places to) that babies need some exposure to bugs to build up their immune systems and prevent allergies.