Canned food has a long shelf life because the sterilized food is separated from the outside environment by the sealed containers (i.e., metal can, glass can, and aluminum foil). Thus, food is not contaminated with outside air or microorganisms. The sealing efficiency directly affects the shelf life of the canned products. Thus, high-quality sealing causes the canned food to have a long shelf life, while low-quality sealing causes the food to have a short shelf life. Most canned foods are sealed using a sealing machine, and a strictly controlled sealing procedure is vital for food storage.