Canning is a method of food preservation. The term is confusing as these days, mason jars are used to can food items. The food is cooked in high temperature and then placed inside sterilized mason jars. It is then tightly sealed to make sure bacteria does not go in, thus preserving the food for the longest time. The tight seal is made by a vacuum sealer like the FoodSaver V3240, a handsome vertical-design sealer that has an accessory port that attaches the hose that can be used on the canisters and mason jars.