Help!

I'm absolutely horrified! Was giving daughter her feed right now, she'd had three ounces already, when I noticed a black lump floating about in the milk! The bottle was washed last night and straight out of the steriliser ( Hubby sterilised them all before bed but I leave them in there and re sterilise and take out fresh before each feed). I have no idea what it was... I can only think maybe a bit of limescale or something or something stuck to the bottle if hubby didn't rinse properly. ???? Obviously I emptied the bottle and made up a new feed but I'm sooooo paranoid that something bad is going to happen ????