The Heat is On

What really stresses these multi-layer structures, says Dabbert, is the need to withstand the sterilization process, which involves high heat and pressurized steam. “That necessitates a package that has excellent heat seal strength, impact strength, and barrier to oxygen and moisture,” he says.

Weaver believes that retort pouches face some of the toughest challenges of any packaging format. “During processing, filled pouches must be able to withstand temperatures up to 275°F [135°C] for periods of 60 minutes or longer, while enduring changes in both internal and external pressures. The laminate and adhesives are under tremendous stress; any failure will adversely affect the hermetic nature of the pouch.”