I just pumped 6 oz and when I went to pour the milk into a bag I noticed some black on a part of the flange. It's not on a part that actually touches the milk, but is it better to be safe than sorry? I'm not sure what the black is but it doesn't scratch off and the flange was washed before I used it. It's breaking my heart to think about throwing all of that milk out. Pics aren't so great but I tried to show what it looks like (black is by the opening of the lid).