A retort pouch is a form of advanced food packaging that has, in many instances, replaced the need for canning. The concept was invented by the United States Army in 1978 as a method of storing rations for troops, known as Meals, Ready-to-Eat (MREs), but it has since been adapted to a wide array of consumer products, even including some pet food snacks. The retort pouch consists of multiple layers of plastic and aluminum, or gold-colored metal foil laminate. It is so durable and puncture resistant that it has earned the name “flexible can.” Some even have see-through windows so that the consumer can view the contents before buying the product