I defrosted some breast milk last night (one month old from freezer.) It was quite yellow and smelled quite strong - not of sour milk, just strong. I also expressed and that was pure white and didn't smell. I know that breast milk colour and smell varies with diet but I was a bit wary so through it out. Also defrosted a couple of other packets which were a more white colour but still smelled much stronger than the fresh stuff. Was too scared to use that so chucked that out. What if my freezer defrosted and refroze whilst on holiday? Have a great stock in the freezer that I was going to use as I slowly stopped breast feeding but I don't know if I trust it.