Overnight mushroom leftovers can be eaten if they are properly preserved, but not if they are moldy or have an off-flavor. Overnight mushroom leftovers can be eaten the next day if they are well preserved in the refrigerator and left for a shorter period of time without deterioration, it is recommended to heat them sufficiently before consumption and not to eat them cold. If placed improperly, such as the temperature is relatively high, caused by the deterioration of mushroom leftovers, the performance of mold production or there is an odor emitted, this situation is not edible. Because the nitrite content in the food is relatively high at this time, which has a negative impact on human health. In addition, it may also harbor a lot of bacteria, which may cause food poisoning after consumption. Therefore, it is recommended to eat fresh food. Overnight food should be carefully identified and consumed as little as possible. If you experience any discomfort after consumption, you should seek medical attention promptly.