i've been donating for months and nit using my own frozen milk. the mom has never said anything and has always gladly taken more.
last week i had to use frozen milk because i had a girls day out and dd stayed in with dh. when i came home, i noticed the bottle of milk smelled plasticy. is this normal. dh said dd had no problem eating all day.
Re: plastic smell
I've noticed that if my DS' water sits in a cup for too long it starts to take on a plasticy flavor and my son won't drink it...Every time I give him water now, I always dump out the old water and put in fresh.
So I would assume the same thing could happen with milk. Target sells a glass bottle, "Born Free". If you're worried about chemicals leaching into the milk, that might be a good thing to try.