Sterilize it how? There's inert yeast and bacteria on your flour at all times. That's what allows you to create a starter from scratch. What do you want to do,

Sterilize it how? There's inert yeast and bacteria on your flour at all times. That's what allows you to create a starter from scratch. What do you want to do, bleach raw flour every time you're about to drop it in your starter? I'm sure if you were in a lab environment and absolutely needed to, there are options to do so. But not for most home bakers.