I have put hot food in it and because it closes airtight, resulting in no air entering and the temperature it develops to rise quickly, it develops mold. I don't know if I did something wrong. It was rice with vegetables. Maybe it’s okay for soups. Anyway, the food stays at temperature whether cold or hot.

Klean Kanteen. Expensive but does the job it's supposed to (I bought it for all-day use). It keeps food warm for five hours and has a wide mouth for easy use. However, I should mention that my six-year-old son struggles to open it and needs someone to help him. (I tighten it just enough to close it properly, not more than that)

Excellent product, for the child's meal during the day. I have been using it for 1 year and I am completely satisfied. The food stays warm and safe for 7 hours as stated. The condition is to prepare it correctly (hot thermos - hot food).