Which retail innovation, first widely implemented during World War II to efficiently supply troops, revolutionized product identification and is now ubiquitous in civilian retail?

Throughout military history, retail strategies and product innovations have played surprising roles in supplying armies and affecting war outcomes. From the introduction of standardized uniforms to military-grade consumer products, retail developments have shaped how nations prepare for and conduct warfare. This trivia question explores a significant retail innovation that transformed military supply chains and eventually influenced civilian retail practices worldwide.

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Barcodes (Universal Product Code)
Self-service grocery stores
Mail-order catalogs
Refrigerated supply chains