what poo heads
i would be putting a sign on the fridge door
"to the people that drank the milk in the babies bottle in the fridge the other day- you drank breastmilk that could have possibly be contaminated! Please come go and get yourself checked by a doctor!"

might be enough for them to cack their pants and go see a doctor who will hopefully scare the crap out of them and give them a stern talking to!!
Joke back on them i say!!

HAHAH my DH just said it should have a sign that said
Who is the bloody idiot that drank the bull semen I had in the baby bottle

I'm pretty sure that would shut them right up :-P