Strictly speaking, once the shelf life of any food has passed, in principle, it cannot be eaten again. Generally speaking, the shelf life is calculated in days. It actually refers to the period of normal storage without deterioration when the packaging is intact under normal circumstances (that is, the natural environment at that time). Obviously, the shelf life is shorter in spring and summer, and longer in autumn and winter. Long, but when the environment is harsh and the temperature is abnormal, the shelf life will be shortened. It is only an approximate value. When it is well sealed and frozen, it can still be eaten after 1 to 2 days of expiration. The shelf life of rusk is longer than that of ordinary bread. For expired bread sensitivity and tolerance. Even if the bread is not stored properly, it may become moldy and spoilage even within the shelf life. Therefore, the main thing is to check the condition of the bread itself. Be sure to carefully identify it before eating. If there are any abnormalities in sensory properties, do not eat it again. If it is determined to be edible, It is still beneficial to heat it in the microwave (heating to soften and sterilize). If you find that the sensory properties of the bread are abnormal or you suspect that there is a problem with the quality of the bread, it is best not to eat it. When mold grows on the surface of bread, the entire bread is actually in a state of spoilage from the inside out, but the mold will appear on the surface first. Even if part of the bread is cut off, the rest will still be contaminated by the mold, which will still cause food poisoning. Note when storing: If the interval is not long and the room temperature is not very harsh, it does not matter if you leave it overnight for a few hours (the packaging must be intact). If the time interval is long, it is better to freeze it. Refrigeration will cause the Bread ages quickly, has a poor taste, and can absorb odor or absorb moisture and become gelatinized. Anyway, it is best to heat it before eating, and freezing is more suitable.