If i took out my frozen breastmilk and keep in the normal fridge to slowly defroze it, how long can it last?

Usually after you put down to defrost, need to consume within 24 hrs. But I've tried max 48hrs and it was ok. Basically my fridge takes super long to defrost. I can take down from the freezer to the fridge for a day and maybe only 20% defrosted. With such a rate, i left it there for another day. SO far as been so good for my baby.