Which famous product innovation, developed during WWII, revolutionized portable military rations and later became a successful civilian product still sold today?

Throughout military history, feeding troops has been a critical logistical challenge. The development of combat rations represents one of the most significant product innovations in military history, directly impacting soldier effectiveness and morale. From ancient armies carrying dried meat to modern forces with scientifically formulated Meals Ready to Eat (MREs), the evolution of military food technology reflects broader advances in product development, preservation techniques, and nutritional science.

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M&M's candies (designed to allow soldiers to carry chocolate that wouldn't melt in tropical environments)
SPAM (Special Processed American Meat, which provided shelf-stable protein to troops)
Instant coffee crystals (developed for quick caffeination in combat conditions)
K-rations (complete meal kits that influenced modern packaged food design)