Aesthetic considerations also had to be addressed. Because food migrates to the edges of the pouch during retorting, engineers had to design a secondary barrier to shield the zipper and prevent food from crusting around it. Both Zip-Pak and Presto Products in Appleton, Wis., addressed the issue with multiple designs, depending on how the pouch is filled.
For top-fill pouches, Presto's Fresh-Lock engineers came up with an elongated flange that is sealed to the pouch wall and creates a barrier to product migration, according to Product Manager Tom Winter. For bottom-fill pouches, a unique membrane is incorporated into the design.
Fresh-Lock's partner in reclosable retort pouches is Pyramid Flexible Packaging. "There's major interest from U.S. manufacturers of soups, stews and other foods, but pet food is probably a safe bet" to be the first commercial product in the U.S. market, predicts Winter.
Pet food was the first non-MRE application of the retortable pouch, Hogan points out. Even greater potential may exist with large pouches for foodservice operators, he believes.
For more information:
Thomas A. Winter, Presto Products Co., 920-738-1747,
Robert E. Hogan, Zip-Pak International, 800-488-6973,