High pressure pasteurizable/ultra-high pressure sterilizable food processing container and method

Abstract

A method and container capable of withstanding ultra-high pressure sterilization or pasteurization and being used as a retail package. The container includes at least one deformable pressure absorbing fold channel integrally formed therein enabling the container to undergo UHP processing and return substantially to its prior shape. In one embodiment, the container has at least one sidewall with such a fold channel. In a preferred embodiment, the package also has a bottom wall with a fold channel. The container is thermoformed of a sheet that includes at least one oxygen barrier layer and includes a peelable oxygen barrier film covering a container opening. In a preferred method, the container has a plurality of sidewalls with a fold channel therebetween and a bottom with a fold channel thereabout that accommodates compression between 5% and 25% without showing visible damage when subjected to pressures of between 70 ksi and 120 ksi.

1 . A container for use in high pressure sterilization comprised of at least one sidewall and a fold region formed of a multi-layer sheet having an oxygen barrier and a oxygen barrier film sealing an opening thereof. 
   
   
       2 . The high pressure sterilizable container of  claim 1  wherein the multi-layer sheet is comprised of a layer of an oxygen barrier material and at least one layer of a polymer. 
   
   
       3 . The high pressure sterilizable container of  claim 2  wherein the multi-layer sheet comprises a plurality of outer layers of polypropylene and an inner layer comprised of an oxygen barrier material. 
   
   
       4 . The high pressure sterilizable container of  claim 3  wherein the oxygen barrier material comprises one of Ethylene Vinyl Alcohol and Polyvinylidene Chloride. 
   
   
       5 . The high pressure sterilizable container of  claim 1  wherein the sidewall and fold region are integrally formed of the multi-layer sheet forming a container of one piece, substantially homogenous and unitary construction to which the oxygen barrier film is attached. 
   
   
       6 . The high pressure sterilizable container of  claim 5  wherein the fold region has an arcuate transverse cross-section, is elongate, and extends generally longitudinally. 
   
   
       7 . The high pressure sterilizable container of  claim 6  comprising a plurality of sidewalls with a fold region extending therebetween. 
   
   
       8 . The high pressure sterilizable container of  claim 7  comprising a plurality of pairs of sidewalls and wherein there is a fold region extending therebetween that comprises a fold channel. 
   
   
       8 . The high pressure sterilizable container of  claim 5  wherein the fold region extends generally transversely. 
   
   
       9 . The high pressure sterilizable container of  claim 9  further comprising a bottom wherein the fold region extends along a portion of the bottom. 
   
   
       10 . The high pressure sterilizable container of  claim 10  wherein the fold region comprises a channel that extends about a portion of the bottom. 
   
   
       11 . A high-pressure container for use in food sterilization comprising:
 a bottom comprised of a first integrally formed fold region;   a plurality of sides extending upwardly from the bottom comprising a second integrally formed fold region; and   wherein the container is configured to buckle under the application of high pressure of at least 70 kpsi and return substantially to its initial shape after application of the pressure.   
   
   
       12 . The container of  claim 11  wherein the container is composed of a multi-layer sheet material. 
   
   
       13 . The container of  claim 12  wherein the multi-layer sheet material includes at least one layer of a co-polymer adapted to serve as a liquid barrier. 
   
   
       14 . The container of  claim 13  wherein the co-polymer comprises polypropylene. 
   
   
       15 . The container of  claim 13  wherein the multi-layer sheet material includes at least one layer of an oxygen barrier material. 
   
   
       16 . The container of  claim 15  wherein the oxygen barrier material comprises EVOH. 
   
   
       17 . The container of  claim 11  further comprising a removable film adapted to be secured to the upper surface of the container and configured to serve as an oxygen barrier. 
   
   
       18 . The container of  claim 11  further comprising a removable lid secured to the upper surface of the container. 
   
   
       19 . A method of high pressure sterilization of food product comprising the steps of:
 providing a container having a sidewall and at least one fold region;   packaging perishable food product in the container;   placing the container in a vessel configured for high pressure sterilization;   filling in the vessel with water; and   pressurizing the vessel so as to sterilize the food product to a pressure of at least 70 kpsi;   wherein the container is configured to buckle during the pressurization of the vessel and return substantially to its initial shape after the pressurizing.   
   
   
       20 . The method of  claim 19  wherein the fold region comprises a channel configured to buckle during the pressurizing of the vessel.