Which foods can be sealed? Dried foods, frozen foods and those foods that are refrigerated can be extended using a vacuum sealing machine. However, it is important to avoid developing a false sense of security. Food that is vacuum-sealed and then frozen is safe, but it is best to thaw it in the refrigerator in order to slow the growth of bacteria. Perishable items of food that are vacuum packed should remain in the refrigerator and not be in an area with a temperature above 40 degrees for longer than a total of two hours. This guideline is for safety reasons and should always be followed. Keep in mind that removal of oxygen from food packages does not remove the growth of all bacteria.