Retort processing of food in rigid, semi-rigid and flexible packaging systems is the most acceptable form of food preservation. Cans, Pouches, Plastic Bottles, Bowls, Cups, Glass Bottles, Cartons etc are being used for packing retort food products.

The processor should select the suitable retort, filling machine, process technology and utilities based on the type of containers used. Flexible containers like pouches, semi rigid containers like plastic containers etc. require what is known as “ overpressure sterilization process “.

Overpressure sterilization means that air is introduced into the retort during sterilization, as a means of adding pressure around the outside of the containers to prevent container deformation. As the thin-walled containers (such as pouches) begin to heat and mix with the gases inside oof the container, the internal container pressure increases at an increasing rate. Without sufficient external pressure, greater than that supplied by steam alone, the container will deform or rupture. Hence Overpressure Sterilization Process is required to process products in such containers.