For two weeks last September, fresh spinach disappeared from grocery store shelves. The Food and Drug Administration recalled all spinach after E. coli-tainted leaves sickened hundreds of people.

Using the bar code on a bag of bad spinach, investigators traced its origin to California's Salinas Valley. Then began a painstaking search for the grower, all the while spinach was being pulled from grocery stores, distribution plants, and processing plants and destroyed. A growers' organization estimates the recall cost the spinach industry as much as $74 million.

RFID helps the meat industry figure out where the beef is Photo by Mike Cassese/Reuters

It would have been much faster to track the contaminated leaves to the grower if spinach bags and containers had carried radio frequency identification tags with complete histories of the contents' origins. RFID tags can hold considerably more data than bar codes and are more easily read because they don't require a line-of-sight connection to a bar-code reader. So what's the holdup? Silicon RFID chips still cost too much. To use them for item-level tagging, they would have to cost less than 1 cent, and considering the required components--an antenna and a microchip--that may never happen.

Get rid of the silicon and RFID could work for the food industry. Fortunately, several companies are developing silicon-free alternatives. PolyIC, half-owned by Siemens, is working on RFID tags made by printing electrically conducting and semiconducting polymers on polymer film. PolyIC recently announced that it has developed a printing process that lets it produce miles of the plastic tags, and it plans to produce 13.56-MHz high-frequency RFID tags this year.

OrganicID, recently acquired by Weyerhaeuser, has invented an RFID tag based on paper, creating circuits through the layering of electronic ink that costs less than a cent. Weyerhaeuser plans to market the tags to the consumer goods and retail industries.

Somark Innovations has developed a nontoxic RFID ink it says can be stamped onto meat. Somark will market its product to the cattle industry, which is being asked to comply with the Department of Agriculture's National Animal Identification System. The agency began working on the national ID system after a cow infected with mad cow disease was found in the United States in 2003. The system, which is expected to be in place in two years, will provide every newborn calf with a 15-digit identification number and will include databases managed by states and industry groups.

The food industry has experience with RFID. Some manufacturers are working to comply with Wal-Mart Stores' pallet-level tagging requirement, for example. And some processors, such as Atlantic Beef Products, are trying new tracking methods. The Ontario beef-processing facility is using RFID to record data on cow carcasses and the resulting cuts of meat as they travel through its processing plant and on to distributors (see story, below).

Item-level RFID tagging has the potential to increase food safety and cut costs in the food supply chain by improving stock management, expanding theft controls, and expediting the retail checkout process. Concerns are rising over food tainted in the supply chain because of sloppy processing practices, and the Department of Homeland Security considers bioterrorism to be among the biggest threats facing the country.