Pressure Processing method for food materials

A pressure processing method for flowable food materials, employing at least a first and second pressure container, each pressure container liquid tightly housing therein a free piston which is slidable axially in the container, wherein each of said free pistons partitions each container into a first pressure chamber for receiving a pressure medium and a second pressure processing chamber for receiving flowable food material to be pressure processed by being subjected to pressure greater than atmospheric pressure, each of said free pistons being configured to prevent mixture and contact between the pressure medium and the flowable food material when the pressure medium and the flowable food material are in the first and second chambers, respectively, and each of said free pistons being freely movable to equilibrium positions having equal fluid pressures in each of their respective chambers, comprising the steps of:

• pressure processing flowable food material that has already been supplied to the second chamber of the first container by applying fluid pressure to the first chamber of the first container, such that the fluid pressure in the first chamber pressurizes the second chamber of the first container to a pressure greater than atmospheric pressure, and holding said flowable food material in the second chamber of the first container under said pressure for a time sufficient to pressure process the flowable food material;
• simultaneously with said pressure processing step, supplying additional flowable food material to be pressure processed to the second chamber of the second container;
• and
• terminating said pressure processing step in said first container and initiating a pressure processing step in said second container by fluidically communicating said first chamber of said second container with said first chamber of said first container so that the fluid pressure in said first chamber of said first container is applied to said first chamber of said second container.