Which packaging innovation, first widely deployed during World War II, revolutionized military rations and later became common in civilian food products?

Throughout military history, the way nations have fed their troops has significantly impacted campaign success. From ancient Roman 'bucellatum' hardtack to modern MREs (Meals, Ready-to-Eat), the packaging, preservation, and distribution of military rations represents a fascinating aspect of military logistics and product development. This trivia question explores a revolutionary packaging innovation that changed battlefield nutrition during a pivotal period in military history.

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Vacuum-sealed tin cans
LDPE (Low-density polyethylene) pouches
The K-Ration's waxed paperboard boxes
Aluminum foil wrapping