Whether you do meal prep or you just have leftovers to put away, it’s best you let the food cool down before packing it away in a fridge. Why? Because putting hot foods into a fridge will not allow the food to cool down quick enough to escape the ‘danger zone’ of 140° F (60° C) to 40° F (4° C) within 2 hours, which is the general amount of time it takes for food to go bad within that zone.