I'm at a loss, and I'm hoping y'all can figure out why this happened.

I weaned over the last week, and have been giving LO the last of my frozen stash. The last three bags I opened were from late September, and every single one had gone bad. The one I fed her tonight smelled ok, but she vomited it back up all over me.

The bags were in the bottom basket towards the back of the freezer, hadn't leaked, and had only been frozen two months. I thawed them in the fridge and used within 24 hours.

Any ideas? I'd really hate to repeat whatever mistake I made with #2.