trixie, my daughter makes 2 smoothies each morning for her son (toddler age), one for a morning snack and one to eat in the later part of the afternoon. They keep fine. Of course, his tastes may not be as discriminating as an adult's. You can use the Thermos cold/hot stainless steel unbreakable food containers. They keep hot food hot 5 hours, cold food cold for 7 hours. I have a couple and they really work well. They eliminate the need for a cooler, and there's no need to heat the food at your destination.
http://www.thermos.com/product_deta...de=FOOD&q=