Method of Packing a Food and of Heat Treating It for Purposes of Extending Its Shelf-Life

A method of packing a food and heat treating the food for purposes of extending its shelf-life, comprising:

• filling food into an open packaging container made of a packaging laminate comprising a core layer of paper or paperboard and outer layers of polyethylene;
• closing and sealing the packaging container filled with food to produce a filled and sealed packaging container;
• feeding the filled and sealed packaging container into a treatment chamber or tunnel provided with an inlet and outlet, in which the packaging container is conveyed in sequence through a heating zone in which the food is heated to a desired treatment temperature, a holding zone in which the food is kept at the desired treatment temperature during a sufficient period of time in order to exterminate, deactivate or otherwise eliminate undesirable microorganisms, and a cooling zone in which the food is cooled;
• removing the filled and sealed packaging container from the treatment chamber or the tunnel for further transport and handling;
• the filled and sealed packaging container is, in both the heating zone and in the holding zone, heated by a liquid heating medium;
• and
• the filled and sealed packaging container is, throughout the entire transport through the heating zone and the holding zone, subjected to an outer support pressure.