WASHINGTON – In the long search for the origins of the salmonella outbreak, the Food and Drug Administration has finally settled on a single product (jalapeño peppers) and a country (Mexico).

But the four-month search hasn't been easy. Although a lot of the pieces for a rapid-response system already exist, nobody has quite figured out how to put them together to operate seamlessly in the vast American marketplace.

The salmonella outbreak has set off a scramble among industry, regulators and lawmakers to devise a system that would allow food to be traced quickly through a serpentine supply chain that spans nations and continents.

"We clearly have the technology to trace food from field to fork, but we don't have any national system to coordinate it," said Rep. Diana DeGette, D-Colo.

In the salmonella case, investigators were slowed by having to sift through batches of paper records at multiple facilities that handle packing and distribution. It got even more complicated because tomatoes from different farms in widely separated locations are routinely mixed together for shipping to markets. Disease detectives were unable to find a contaminated tomato, though they did find the outbreak strain on a jalapeño pepper.

It needn't be that complicated. In Canada, for example, ranchers can produce a FedEx-style report showing farms, auction pens and feed lots their cattle stopped in from birth to slaughterhouse – a technology now being adapted for some U.S. produce farms.

Dr. David Acheson, the Food and Drug Administration's food safety chief, says a better tracing system needs three key components: a unique identifier that follows each food item from field to consumer, electronic record-keeping and a common framework for sharing information among all the players.

"It is unquestionable that we need to put more emphasis on the importance of traceability," said Dr. Acheson. "Tracing foods back can be really tough, or pretty straightforward, depending on the system."

On Friday, the FDA narrowed its warning about eating jalapeño peppers to cover only those grown in Mexico. That was a relief for U.S. growers, but some also said it confirmed that the agency's earlier alert was too broad.

The FDA is trying to determine whether it has the legal authority to require a better tracing system, but ultimately it may take a congressional mandate.

Rep. John Dingell, D-Mich., is working on legislation that would incorporate a tracing system, and he hopes to bring it to a floor vote this year. His House Energy and Commerce Committee will hold a hearing into the salmonella outbreak next week.

Some legal underpinnings for a national tracing system are already in place. A federal bioterrorism law requires food to be traced one step forward and one step back – who supplied it, and where it went – so that, in theory, regulators can follow the trail. And a federal law that becomes effective later this year will require a country-of-origin label for all food, even if it's U.S.-grown. Those labels provide an opportunity to add extra information, such as a unique tracking number.

The food industry has resisted stronger tracing requirements. But with estimated losses from the salmonella outbreak mounting to $250 million for tomato growers alone, that's starting to change.

In Florida, for example, farmer-backed tomato "best practice" requirements took effect this summer that include some tracing provisions. But with national food distribution, state-by-state rules would have little impact.

"My impression is that before this tomato-pepper outbreak, the industry really didn't want trace-back, because if they had a problem, they didn't want it traced to a specific grower," said Michael Doyle, director of the Center for Food Safety at the University of Georgia. "Now, seeing that what can happen can shut down the whole industry, I would think it's to their advantage to enable trace-back investigations to focus on the source."

Even if the government doesn't require tracing, some major retailers do.

"We like to get back to the dirt, or in the case of tomatoes, the hothouse," said Craig Wilson, assistant vice president for food safety and quality at Costco. Verifying the supply chain is a specification, just as freshness would be. Vendors are required to maintain records, which Costco audits at least annually.

To date, the CDC has confirmed 1,294 people sickened from the outbreak. It doesn't appear to be over yet, with people falling ill as late as July 10.