Method of purging air from containers

Claim 1

A method of packaging and sterilizing a water containing product and purging gases from the headspace of a pouch filled with the water-containing product and formed by the walls of a plastic-aluminum laminate with each wall including an aluminum layer laminated to an inner layer of heat sealable hydrogen and water diffusible plastic and having all edges of the walls except an edge which defines a mouth sealed together; comprising the steps of forming a one-way valve in the pouch, subjecting the pouch to a heat treatment medium maintained at atmospheric pressure and at a temperature above the boiling point of water for a period sufficient to sterilize the product, maintaining said heat treatment for a period sufficient to form steam and hydrogen in the pouch in sufficient quantities and at a sufficient pressure for opening the one-way valve and purging headspace gases from the pouch, and thereafter sealing the pouch before air can enter the pouch to provide a gas in the headspace that is rich in hydrogen.

Claim 2

A method of packaging and sterilizing a water containing product and purging gases from the headspace of a container filled with the water containing product and formed by walls of a plastic laminate on aluminum with each wall including an inner hydrogen and water diffusible plastic layer and an aluminum layer with all edges of the walls except an edge which defines a mouth sealed together; comprising the steps of supporting the container, subjecting the container to a heat treatment medium maintained at temperatures above the boiling point from about 212* F to 250*F at atmospheric pressure of water for a period sufficient to sterilize the product, maintaining said heat treatment for a period sufficient to form steam and hydrogen in the container in sufficient quantities for purging air and cooking gases from the container, and thereafter sealing the container before air can enter the container to provide a gas in the headspace that is rich in hydrogen.

Claim 6

A method of packaging and sterilizing a water-containing product and purging gases from the headspace of a pouch filled with the water containing product and formed by walls of a plastic-aluminum laminate with each wall including an aluminum layer laminated to an inner layer of heat sealable hydrogen and water diffusible plastic having all edges of the walls except an edge defining a mouth sealed together; comprising the steps of forming a one-way valve in the mouth of the pouch, continuously moving the pouch along a predetermined path, immersing the pouch in a liquid to purge the headspace gases therefrom, heating the pouch to a sterilizing temperature while immersed in the liquid for forming steam in the pouch, continuing said heating for a sufficient period for causing water to diffuse through the inner plastic layers of the pouch and react with the aluminum forming hydrogen that diffuses back through the inner layers into and pouch, the pressure of accumulated steam and hydrogen within the pouch being effective to open the one-way valve and purge additional quantities of headspace gases therefrom, and thereafter sealing the mouth of the pouch before air can enter the pouch to provide a gas in the headspace that is rich in hydrogen.