On the morning of June 26, 1974, at a supermarket in Troy, Ohio, a pack of Wrigley's Juicy Fruit chewing gum becomes the first grocery item scanned with a Universal Product Code, or UPC. The result of years of scientific experimentation and industry cooperation, the UPC barcode would go on to be used well beyond the grocery checkout counter, becoming a ubiquitous feature of modern commerce, with billions of barcodes scanned daily.

The first version of a barcode was drafted by inventor Joe Woodland in the sand on Miami Beach in 1949. He designed a pattern of thick and thin lines arranged in concentric circles, readable by a scanner from any angle. Woodland took the inspiration for his design from Morse Code, but instead of communicating through dots and dashes, the barcode relayed information through thick and thin lines. He applied for a patent for his invention in 1949 and received it in 1952.

It took two decades to translate Woodland's idea into a functional barcode scanning system. In 1949, there was no practical way to "read" a barcode's image. The invention of the laser in 1960 created new possibilities for scanning technology.  At the same time, computers became smaller and more affordable. Barcode scanners took advantage of both these advances. The new scanners used the ultra-bright light of a laser to sweep across the black-and-white image of a barcode, communicating information about the product and the price to a computerized cash register.

Grocery industry executives recognized the potential of these new technologies to improve efficiency and keep costs down in their stores. They also realized that they needed a standardized system to effectively introduce barcodes industry-wide. The "Ad Hoc Committee of the Grocery Industry" convened in 1970 to develop a plan for implementing barcodes and scanners at the nation's grocery checkouts. Kroger, independently, became the first store to install a pilot program of barcode scanners in their stores in 1972. Kroger and RCA collaborated on an automated supermarket checkstand, which used Woodland's "bull's-eye" barcode design.

The round design proved somewhat unreliable, however, because it tended to get smudged coming out of the printer. The Ad Hoc Committee selected a different design, based on a last-minute submission by IBM engineer George Laurer. He redesigned the barcode as a rectangle, rather than a bull's-eye, which made the image easier to print accurately. Laurer's winning design, named the Universal Product Code (UPC), combined vertical stripes with a row of 12 digits. Clyde Dawson, head of research and development for Marsh Supermarkets, ceremonially scanned the first grocery item with a UPC on June 26, 1974, at 8:01 a.m. It was a pack of Wrigley's chewing gum, proving that barcodes could work on even the smallest items.

The new barcodes and scanners in grocery stores garnered mixed reactions from shoppers, however. Some thought the lines and numbers represented the "mark of the beast" from the biblical Book of Revelation. More widespread was the belief that barcodes would provide stores with a new way to rip off customers. The Consumer Federation of America launched a campaign against barcodes nationwide, and protesters picketed stores with barcode scanners. The U.S. Senate even held a "symposium on the Universal Product Coding System." Due to the pushback from customers, grocery stores were slow to embrace barcode scanners, with only 1 percent adopting the new devices by the end of the 1970s. A decade later, however, the consumer backlash had ebbed, and more than half of U.S. grocery stores relied on UPC scanners. Since then, it has become arguably the most pervasive technology of the retail shopping experience.