Remember when bar codes were new and exotic? If you do, you might not be as young as you think. The now-ubiquitous black-and-white striped Universal Product Code celebrated its 35th birthday on June 1.

A giant U.P.C.-decorated birthday cake was the centerpiece of a party held at last month's Annual U Connect Conference put on by GS1 US, the developer and administrator of the U.P.C. in the United States.

The code, which today consists of 59 machine-readable bars and 12 digits that identify the item and its manufacturer, was originally designed to speed up grocery checkouts. The first live U.P.C. scan occurred on June 26, 1974, when a cashier at a Marsh supermarket in Troy, Ohio, scanned a pack of Wrigley's gum. The productivity improvements since then have saved retailers, manufacturers, and consumers billions of dollars. Now adopted by more than 25 industries, U.P.C. codes are scanned more than 10 billion times each day, according to GS1 US.