July 15, 2008
Seeds of Doubt Sown in Salmonella Case
SANTA YNEZ, Calif.--This year was shaping up to be a good one for farmer Ernesto Ramirez, who will harvest 80 acres of jalapeno and serrano peppers in two weeks. Not only was his crop good, but Ramirez had taken expensive steps to ensure that it remained that way, hiring an outside agency to certify his worker training and the cleanliness of his land and water.
But a week ago came word that peppers like the ones Ramirez grows have been implicated in one of the largest and most perplexing food-borne illness outbreaks in modern memory. More than 1,000 people have fallen ill from salmonella, a bacterium that public health officials now believe has been transported by tomatoes, jalapeno and serrano peppers, even cilantro."Like farming isn't a gamble already?" said Ramirez, 47. "It's scary when you don't know what's going to happen to an industry."
The vexing nature of the outbreak has revealed serious gaps in America's food safety system, a loose network of local, state and federal health agencies that trade information when illnesses occur.
The failure of the Centers for Disease Control and Prevention and the Food and Drug Administration to definitively link the illnesses to a food has invited even more criticism following a year of contentious food recalls and contamination cases.
"Our food network has changed over the last 20 years," said Rep. Diana DeGette (D-Colo.). "We have more imported food. More food is distributed nationally. But the food safety system has not changed with it."
No 100% certainty
Most states learn of food-borne illness outbreaks through a CDC program called PulseNet, which works something like weather radar. States report cases of food-borne illnesses to the CDC, and they're tracked on PulseNet. When similar illnesses start to show up--usually regionally or in clusters --CDC epidemiologists know a storm is brewing.
Sometimes PulseNet notices outbreaks before states do. In the case of the salmonella outbreak, for instance, Texas officials did not recognize a problem at first. Linda Gaul, an epidemiologist and head of the state's food-borne illness department, said Texas has about 3,000 salmonella cases annually, so patterns aren't always apparent.
But when the state received word from CDC in late May that salmonella strains in Texas matched those in neighboring New Mexico, health authorities were alarmed, she said.
Health scientists from the CDC, FDA, Texas and New Mexico began a series of daily and weekend conference calls to discuss the outbreak. Both states had begun interviewing salmonella victims, many of whom said they had eaten raw tomatoes before getting sick.
On May 31, the FDA told the conference-call participants that it wanted to issue a warning to consumers to avoid red plum, Roma and red round tomatoes. It did so on June 3 for Texas and New Mexico, and then expanded the alert nationwide four days later.
"You never have 100 percent certainty," Gaul said. "We felt pretty comfortable about it, or we wouldn't have notified anyone."
But people continued to get sick.
Tomato growers soon got irate, arguing that the outbreak might be limited to a small area--even one farm--but that tomato sales nationwide were plummeting. Their irritation grew into contempt when the FDA later issued a list of states where tomatoes were considered safe, and then conceded that foods other than tomatoes could be to blame.
"It's jalapenos this week and cilantro next week and then it's back to tomatoes," said Robert Schueller of Melissa's World Variety Produce in Los Angeles, a produce distributor. "Who knows what it is? For a problem that occurred in so many states, you think it would be easier to solve it."
David Acheson, the FDA's food safety czar, defended the agency's warning.
"If we feel we've got strong enough evidence to warn consumers about the products that might be contaminated with salmonella, we have to do that," he said.
FDA critics such as DeGette argue that the real problem has been the inability to "trace back" suspect tomatoes to their source, where salmonella might be found. FDA officials said that tracing back produce is more difficult for products that are canned, boxed or bagged with bar codes. Nonetheless, Acheson said the agency is trying.
Produce industry representatives, however, take issue with the complaint that fruits and vegetables are tough to trace.
"The problem has been epidemiology, not trace-back," said Jim Prevor, who is editor in chief of Produce Business magazine and who also produces the Perishable Pundit blog. "There are three big chains in New Mexico, including Wal-Mart. Those three chains have perfect trace-back."
Eliminating the suspects
Prevor is one of the critics who blame the CDC and FDA for not moving quickly to conduct case control studies to test the theory that tomatoes were to blame. Those studies, which are being done now by states, involve interviewing people who ate tomatoes from stores or suspect restaurants but who didn't get sick.
Such studies are standard in epidemiological work because they help eliminate suspect foods. But some food safety experts say they weren't used early enough during the salmonella outbreak to winnow out culprits.
"I commented earlier that I didn't think those had been done yet," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. "Those studies are being done now. We all need to just take a step back. They're moving ahead."
The FDA's Acheson said during a June 20 conference call with reporters that the agency had not pursued case control studies.
"We don't routinely do that as part of our outbreak investigation," he said. "It's an intriguing suggestion. We've been focusing on trying to figure out where the contaminated tomatoes came from."
Michael Martinez reported from California and Stephen J. Hedges from Washington, D.C.