Breastmilk

Candice ivf mama of 2 💕💙

My daughter has a dairy allergy so we switched her to formula about 3 months ago. I had pumped and froze breastmilk and we have decided to test it out to see if she can tolerate it. I just thawed 3 bags in the fridge and they all smell sour. Is this normal? I haven’t given her anything yet because I’m worried it’s not good.