What temperature must canned food be heated to for proper canning?

Canned food must be heated to a temperature of 249°F for proper canning because this high temperature is necessary to effectively kill harmful bacteria, molds, and yeasts that can cause food spoilage and foodborne illness. The heating process is critical in creating a vacuum seal that keeps the contents of the can sterile, helping to preserve the food for an extended period.

The temperature of 249°F is particularly important in pressure canning, as it allows for the successful destruction of Clostridium botulinum spores, which can thrive in low-acid foods. Achieving this temperature typically requires the use of a pressure canner, as boiling water alone does not reach this level of heat.

Lower temperatures, like 100°F or 150°F, are insufficient for the safe preservation of canned foods, as they do not effectively eliminate pathogens. A temperature of 300°F may also be excessive and could lead to the degradation of the food quality. Proper canning practices are vital for ensuring food safety and providing shelf-stable products.