In response to a new federal food safety law and growing consumer interest, vast amounts of new data are being generated about the complicated path that food takes from field to supermarket shelf.

And, increasingly, some of that information is being offered to curious shoppers, who in some stores can wave a smartphone above an apple or orange and learn instantly where it was grown, who grew it and whether it has been recalled. They can even contact the farmer, if they feel moved.

A provision of the federal food safety law passed last year requires that all players in the country's food supply chain be able to quickly trace from whom they received a food product and to whom they sent it. They'll have to maintain that information in digital form, creating deep wells of information that, in some cases, consumers could tap into through their computers or cellphones.

The "one step forward, one step back" traceability requirement - for processed food and produce - is designed to make it easier for the Food and Drug Administration to identify the source of an outbreak of foodborne illness, trace its path and swiftly remove it from the food supply.

The new requirement represents a major adjustment for some parts of the nation's food system, as the government imposes standards and electronic record-keeping on an industry where small players still rely on handshakes and paper invoices.

The FDA has had trouble quickly pinpointing the source of national outbreaks of food-borne illness, a task complicated by a lengthy food supply chain where tomatoes might change hands five times from farm to store.

Many in the food business already are using traceability technology, mostly relying on bar codes that can be affixed after harvesting to a piece of fruit or a crate.

But the new law has triggered a small gold rush for technology companies angling for a piece of an emerging market, which covers food other than meat, poultry and egg products. They are competing to develop the tracking technology and manage the data.

Some are experimenting with radio frequency identification and other sophisticated methods, including etching identification codes on produce with lasers or micro-percussion markers that make tiny indents.

"They each believe they have the holy grail product tracking solutions sitting in their laptop," said David Acheson, former assistant commissioner for food protection at the FDA. "Somebody is probably going to make a bundle of money out of this."

Under the new law, the FDA must launch pilot projects by September, then report results to Congress and issue more specific rules by 2013. Exactly what systems will ultimately look like, how they will work and how much they will cost is unclear.

Paul Chang, who leads the traceability initiative at IBM, said the company is basically taking the tracking system it uses for the pharmaceutical industry and adopting it to the food business.