Never put hot food into a refrigerator, as this will increase the internal temperature to an unsafe level. Cool leftover food quickly to room temperature, ideally by transferring it to a cold dish, then refrigerate. Cool large dishes such as casseroles by putting the dish in a sink of cold, or better still iced water. Once cool, refrigerate.
Reheated food must be piping hot throughout before comsumption. Never reheat any type of food more than once.