Bottled breast milk on a day out?


We're gonna be out and about pretty much all day and i exclusively pump and I try to get her to latch but she doesn't and today we're gonna be busy. So I was curious to know if it'll be okay to have breast milk on the go? I know it probably needs to be warmed up but is it okay if it's not? I really don't want to give her formula if I don't have to. Can I pump and take that fresh milk with us? Or is it a no go all together and I have to give her formula?