Heating medium injectors and injection methods for heating foodstuffs

A heating medium injector including:

• (a) an injector structure extending along an injector axis from a first end to an outlet end;
• (b) a heating medium flow path defined within the injector structure, the heating medium flow path extending from a heating medium inlet opening to a contact location;
• (c) a product flow path defined within the injector structure, the product flow path extending from a product inlet opening to the contact location, the product flow path in a first region being defined between a first flow surface and a second flow surface, the first flow surface comprising a surface of a first boundary wall separating the heating medium flow path from the product flow path in the first region and the second flow surface comprising a surface of a second boundary wall;
• (d) the contact location comprising a location within the injector structure at which the heating medium flow path and product flow path first merge in a direction from the first end of the injector structure to the outlet end of the injector structure;
• and
• (e) at least some of the second flow surface of the product flow path is in substantial thermal communication with a second flow surface cooling structure formed within or connected to the second boundary wall and isolated from the product flow path.