Canning is a method of preserving food by first heating it to a temperature that destroys contaminating micro-organisms, and then sealing it in air-tight jars or cans. Because of the danger of botulism, the only safe method of canning most foods is under conditions of both high heat and pressure. Foods that must be pressure canned include all vegetables, meats, seafood, poultry, and dairy products. The only foods that may be safely canned in a boiling water bath (without high pressure) are highly acidic foods like fruits, pickled vegetables, or other foods to which acid has been added.

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