In 2002 Durand-Wayland, a fruit grower and distributor in Georgia, bought the patent for a process that etches the price look-up number and any other information the retailer or customer might desire directly into the skin of the fruit. Greg Drouillard, who originally patented laser coding for produce and who now works for Durand-Wayland, said the process permanently tattoos each piece of fruit, removing only the outer pigment to reveal a contrasting layer underneath and make the tattoo readable, even scannable.

The stickerless technology has a broader purpose, too: it is part of the produce industry's latest effort to identify and track, whether for profit or for security, everything Americans eat. Since 9/11, the industry has been encouraged to develop "track and trace" technology to allow protection of the food supply at various stages of distribution. In addition, next year federal regulations will require all imported produce to be labeled with the country of origin.

To producers, the stickers are messy, expensive and inefficient. "The industry knows that the days of the P.L.U. sticker are numbered and that there will have to be new systems," said Don Harris, vice president for produce at Wild Oats, a national chain of markets, and chairman of the Produce Electronic Identification Board, an industry group. "Customers do not like them, and they don't hold enough information anyway."