Doesn't really matter if it's before or after the hop additions. I put a jar and lid in a hop bag, and let it sit in the boiling wort for about fifteen minutes to sanitize them. Then pull the whole thing out, dip the jar back into the hot wort (with some tongs), put the lid on and call it good. Be sure to use a jar that can withstand the heat like a canning jar.
I've never had a problem with my starters using this method.