Abstract: Food products, such as vegetables, fruits, etc. are efficiently sterilized and/or cooked and canned under high vacuum by filling them into containers, e.g. conventional tin cans, in the presence of only a small amount of water; then securing lids non-sealingly to the open ends of the cans; then passing the cans over a high temperature heat source for direct flame or radiation heating, with their axes inclined, until the liquid collected in a bottom region of each can has come to a boil and the steam formed has driven the free air from the can; then sealing lids tight to the can bodies; then heating the cans to the desired temperature of sterilization and/or cooking and maintaining this temperature for a predetermined period of time; and finally cooling the cans, e.g. by a water spray, whereupon a vacuum of about 700 mm. (27 to 29 inches) of mercury is formed in each can by condensation of the steam therein.