A retort pouch is a type of food packaging created by aseptic processing, made from multiple layers of flexible laminate, allowing for the sterile packaging of a wide variety of food and drink, ranging from water to fully-cooked, thermo stabilized (heat-treated) high-caloric (1300 on average) meals such as Meals, Ready-to-Eat (MREs), which can be eaten cold, warmed by submersing in hot water.
A retort pouch is constructed from a flexible metal-plastic laminate, which is able to withstand thermal processing via sterilization. The food is first prepared, even raw or semi-cooked, and then sealed into the retort pouch. The pouch is then heated to 240-250 0 F (116-1210 C) for several minutes under high pressure, inside retort or autoclave machines. The food inside is cooked, similar to pressure cooking. This process reliably kills all commonly occurring micro organisms (particularly Clostridium botulinum), preventing it from spoiling. The packaging process is very similar to canning, except that the package itself is flexible The lamination structure doesn't allow permeation of gases from outside into the pouch. The particular retort pouches used for several products consists of four layers bonded in a lamination machine.