Steam-flush-water-seal technique for removal of headspace air in retort pouches to near-zero levels

A technique based on steam flushing and consequent formation of a hermetic water seal (thin film of condensed water) in the pouch, near the opening, is described for removal of headspace air in retort pouches. A filled pouch is held taut laterally at the the top, in a specially designed pouch carrier, and steam at 65 kPa pressure is flushed into the headspace through a steam injector for 3 sec. On withdrawal of injector from the pouch at the end of steam flushing, the pouch is closed automatically, resulting in formation of a water seal due to steam condensation