I used to really struggle when out and about, because some places can be so funny about heating baby food and I was always worried in case it wasn't heated properly. I bought one of those thermos things that's like a flask but shorter and wider (if you have a Home Bargains where you live, that's where I got it) and you just heat the food at home then put it in there and it stays the same temperature as you heat it to.
After a while though, I started using pouches any time we're out, as it's very rare that we are out over a mealtime (and not at someone's house!) - saves carrying dishes etc then bringing dirty dishes home.
Hope this helps.
xx