I pumped a bottle the day before yesterday and when my boyfriend picked up our son he forgot to put it in the fridge. It's now been 9 hours since its been out. When I went to go get it the bottle was cold but not refrigerator cold. Our house stays pretty cold so it's like if I would have bought water bottles room temp from the store and came home and left it out it would be cold to the point if I added two ice cubes. I tasted the milk and it was ok but it did have a slight smell. This was 4oz and I cried when I found out it was left out. Right now it's in the fridge but off to the side until I know what's best. Like if I could use it a different way like mic it with oatmeal or something.