“It’s quicker and far more accurate,” Mr. Biddiscombe said. But the system is valuable not only for speeding checkout times and for keeping track of different varieties of bulk vegetables and fruits sold. It also prevents another checkout problem: cashiers mistaking organic vegetables for less expensive, conventionally grown ones, and ringing them up for the lower price.

“The price difference between organic and field tomatoes may be 40 cents a pound or more,” he said. “When they aren’t rung up as organic, that bites into our profit margins.”

Kelly Kirschner, senior marketing manager at Sinclair International, a company in Fresno, Calif., that makes labeling for produce, said DataBars were gradually becoming popular because of limitations of the standard bar code. The standard code, she said, “takes up too much space to be used on loose produce, plus it is for fixed-weight items”  for example, 12-ounce boxes of cereal. The DataBar, by contrast, allows stores to scan for variable weight information.

The labels help stores keep better records, she said. If retailers are receiving Red Delicious apples from three separate suppliers at prices of $8 to $10 a carton, and all the apples are dumped into a single bin, retailers can still tell how many they sold of each lot, as each DataBar is tied to a purchase record.

The next use of DataBars at the supermarket will probably be for goods bought at the delicatessen counter, and for fresh meats and poultry, said Stephen Arens, director, industry development, at GS1 US in Lawrenceville, N.J. GS1 US is the trade organization working to move the DataBar standard forward in the United States. A poultry DataBar, for example, might contain not only the price and product category, but also a sell-by date. If a consumer chose an outdated package, the label would alert the cashier at checkout.