Define Vacuum production and Thermal processing - Canning?

Vacuum production - This can be obtained by filling the heated product into the can, by heating the can and contents after filling, by evacuating the headspace gas in a vacuum chamber, or through injecting superheated steam into the headspace. In every case the can end is seamed on instantly afterwards.

Thermal processing - The filled sealed can should be heated to a high temperature for an adequate length of time to ensure the destruction of spoilage micro-organisms. This is generally performed in an autoclave or retort, in an environment of steam under pressure.