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 (1,300 on average) meals such as Meals, Ready-to-Eat (MREs) which can be eaten cold, warmed by submersing in hot water, or through the use of a flameless ration heater, a meal component introduced by the military in 1992. Retort pouches are used in field rations, space food, camping food, and brands such as Capri Sun, Tasty Bite, etc.
A retort pouch is a plastic and metal foil laminate pouch that is used as an alternative to traditional industrial canning methods. A pouch is a bag with 3 or 4 wide seals, which can store liquid within. Some varieties have a bottom gusset and are known as Stand-Up Pouches.
The retort pouch was invented by the United States Army Natick R&D Command, Reynolds Metals Company, and Continental Flexible Packaging, who jointly received the Food Technology Industrial Achievement Award for its invention in 1978. Retortable pouches are extensively used by the U.S. military for field rations (called Meal, Ready-to-Eat, or MREs).
A retort pouch is constructed from a flexible metal-plastic laminate which is able to withstand thermal processing used for sterilization. The food is first prepared, even raw or cooked, and then sealed into the retort pouch. The pouch is then heated to 240-250°F (116-121°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 microorganisms (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 retort pouch construction varies from application to application, as a liquid product needs different barrier properties than a dry product, similarly an acidic product needs different chemical resistance than a basic product. Some different plastic layers used in retort pouches:
- polyester PET Provides a gloss and rigid layer, may be printed inside.
- nylon Bi-Oriented Polyamide, provides puncture resistance.
- aluminum Al Provides a very thin but effective gas barrier.
- food-grade cast polypropylene or CPP is used as the sealing layer.
- polyethylene (PE) can be used instead of PP as a sealing and bonding layer.
This multi-layer structure prevents the retort pouch from being recycled into other retort pouches or food packaging. However this material can be recycled into an aluminized resin or up-cycled into textile materials. The weight of a pouch is lighter than regular cans or bottles, and the energy required to produce each pouch is less than competing packaging from metals, paper, and glass.
In the consumer market, retort pouches have gained great popularity outside of the United States, particularly in the Pacific Rim region. However, American consumers have evidently demonstrated confusion or reluctance regarding the packaging technology, and its adoption has been slow. As a result, many retort packages sold in the United States are packaged in cartons to give them an appearance more familiar to consumers. Tasty Bite products are an example of a retort pouch product packaged in a carton. Recently,[when?] several American food distributors have begun manufacturing foods in retort pouches without cartons, notably tuna canning companies Star-Kist, Chicken of the Sea, and Bumble Bee.
- Combat Index, “Meals Ready to Eat.” http://www.combatindex.com/. Retrieved on February 6, 2008
- Mykytiuk, Andrew (October 2002). "Retort Flexible Packaging". Flexible Packaging. BNP Media. Retrieved 2009-05-09.
- (Food & Drug Packaging) Retort pouches build up steam: big food companies are taking advantage of technical advances to bring out retorted products in flexible material - Technology: retort packaging 
- Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, ISBN 978-0-470-08704-6