Hi C.,
My name is J. and I am a Lactation Consultant in Sacramento. 1st: Breastmilk (under normal circumstances) never goes bad in 12 hours or 24 hours in the fridge. That information is simply inaccurate. Breastmilk does separate with the fatty milk (hind milk) on top and the more watery (fore milk) on the bottom. Totally normal. Color is not an issue as breastmilk can be shades of many different colors (including green, orange, red, white, blueish...). Sometimes the fat does separate a bit and looks funny - breastmilk is not something we grow up looking at all the time so how would we know what it 'should' look like? :) The key issue here for me is the smell - it shouldn't smell rancid.
However, that being said, Jessica O has it right on the money - some moms have too much Lipase in their milk - we aren't quite sure why but are looking into it. When the milk has too much Lipase it is it starts breaking the milk down and it does start to smell rancid. Very frustrating. Some babies will take it others won't.
How to deal with this? Easy - Scald it. The trick is to figure out how much time you have before the lipase does it's <annoying> thing so that you can scald it. For some moms they have 24 hours - other's - only a couple. Check out the link that Jessica put on for you to kellymom. Great website.
Jessica - thanks for the great information! Not everyone knows about the lipase issue...glad you did!
If you have further questions you are welcome to e-mail me at ____@____.com any time. :)
Warmly,
J. Simpson, IBCLC, CIIM
www.breastfeedingnetwork.net