As consumers abstain from tomatoes or find alternatives, one growers association called over the weekend for Congress to investigate the Food and Drug Administration, the lead agency on the case. The National Restaurant Association, the industry's main trade group, says the outbreak has cost the food industry at least $100 million. And as some crops rot on the vine, the problem is threatening to reignite a long-simmering trade dispute between tomato growers in Florida and Mexico.
Investigators from the FDA have fanned out across farms in Mexico and Florida, two top growing regions, and into irrigation, packing, washing and storage facilities in search of the virulent salmonella Saintpaul strain responsible for the outbreaks. All 1,700 samples they collected were negative, the FDA said in a joint conference call on Friday with the federal Centers for Disease Control and Prevention.
The regulators said they can't pinpoint a region, or even a country, where the outbreak might have started. It might even be possible, they said, that tomatoes aren't to blame. Many victims ate tomatoes combined in dishes such as salsa and guacamole. "We continue to keep an open mind about the possible source of this outbreak," Patricia Griffin, the branch chief of enteric diseases epidemiology at the CDC, said on the Friday conference call.
Dr. Griffin added: "It's very frustrating to all of us to be so far along in an investigation and to not have an answer."
The outbreak's size -- it is the largest produce-linked salmonella outbreak in the U.S., according to the CDC -- and its duration have prompted a sometimes-reluctant shift in consumer behavior. In Austin, Texas, restaurateur Tony Villegas says he has experimented with pico de gallo, a traditional Mexican condiment made with onions, peppers, cilantro and fresh tomatoes, only without the tomatoes. "It was just green and white," said Mr. Villegas. "It tasted really bad, unless you really like onions."
The mystery, and the resulting economic hardship, stems from the sprawling nature of the U.S. food chain, especially the system of distributing fresh produce. In recent years, fruits and vegetables have been responsible for larger-scale outbreaks on average than meat, poultry or eggs. There have been more than 20 incidents since 1995 linked to lettuce, spinach and other leafy greens. Since 1998, there have been 13 salmonella outbreaks linked to tomatoes alone.
Tomatoes are especially vexing because of the complex path they take from field to fork. Because tomatoes are perishable, suppliers typically rely on more than one grower to fill orders. Once the tomatoes come into a processing facility, they're usually sorted based on ripeness, size and grade, not origin. Sometimes, the FDA says, tomatoes picked in Florida are shipped to Mexico for packaging before being returned to the U.S. for sale. Once tomatoes are sliced, diced and mixed for salad bars, deli counters or supermarket salsas, tracking their provenance becomes nearly impossible.
Short of putting bar codes on tomatoes, there's no good way to track their origin, says Ken Albala, a history professor at the University of the Pacific in Stockton, Calif., who writes books about food history.
The FDA relies primarily on growers, processors and retailers of fresh produce to police themselves, an approach that has sparked criticism from consumer groups and even parts of the food industry itself. The Bush administration announced a plan in November 2007 that would allow the FDA to request more authority from Congress, including the power to better trace the source of contaminations. But the agency has made little progress, according to a recent congressional report.
Growers in states most affected by recent outbreaks, such as California and Florida, have taken matters into their own hands. Florida tomato growers, for example, have helped push for new state food-safety regulation that will take effect Tuesday, subjecting themselves to annual inspections and increased training, among other measures.
Cases of Illness
In the current salmonella case, the rare Saintpaul strain has sickened 810 people in 36 states and Washington, D.C., and may have contributed to the death of a Texas cancer patient.
The FDA said on the Friday conference call that it may never find the culprit. "It's important to control expectations, and it's possible that this investigation will not ultimately provide a smoking gun," said David Acheson, the FDA's associate commissioner for foods. "That's not that unusual with tomato outbreaks."
Named for Daniel Salmon, the U.S. scientist who discovered it, salmonella is a feces-borne bacteria that can cause diarrhea, fever and abdominal cramps. Most people recover without treatment, but in severe cases the infection can cause death if it spreads from the intestines to other parts of the body. Salmonella is often found in raw chicken and can be killed if cooked at high enough temperatures.
Scientists haven't figured out how tomatoes are contaminated. Some experiments show bacteria can enter tomatoes submerged in cold water. Others suggest salmonella-contaminated water can enter through the stem or flower of a tomato plant. For now, the FDA recommends consumers avoid raw red round, red plum and red Roma tomatoes unless grown in a state not yet implicated in the outbreak.
The uncertainly has left consumers jittery and many in the tomato industry angry. Over the weekend, Western Growers, a trade group representing most of the fresh-produce industry in California and Arizona, called for the House Agriculture Committee to investigate the regulators.
"The collateral damage inflicted on thousands of innocent producers in this country by FDA blanket 'advisories,' such as with spinach and tomatoes, cannot go unchallenged," said Tom Nassif, the group's president and chief executive, in a written statement.
Dr. Acheson said the FDA regularly provides updates to the industry and wants to keep consumers abreast.
Lisa Lochridge, spokeswoman for the Florida Fruit and Vegetable Association, said the scare could cost hundreds of millions of dollars. "The ripple effect is huge: It's not just the growers but everyone on the supply chain -- the packers, the shippers, on down to food service and the retail level."
No. 2 Seller
Tomatoes are the No. 2 seller in grocery stores' produce sections, behind packaged salad, according to Willard Bishop LLC, a retail consulting firm. Attractive tomatoes also provide a "halo effect" that can make the rest of a produce section look good, said Jim Hertel, managing partner at Willard Bishop. That's important to retailers because consumers primarily judge stores on the quality of their produce, he said.
The salmonella outbreak comes as restaurants are undergoing one of their worst periods in decades, as ingredient costs soar and Americans prepare more meals at home. "The restaurant business doesn't need any excuse for customers to stay away," said Bob Goldin, executive vice president of restaurant consulting firm Technomic Inc.
Most major chains have put tomatoes back on the menu after pulling them several weeks ago, after verifying they come from areas cleared by the government. One company identified as part of the outbreak is Adobo Grill, a small Mexican chain with two locations in Chicago. It did not return a call seeking comment.
In recent years, the food industry has pressured the government to resist pointing fingers. Yum Brands Inc.'s Taco Bell is still recovering from being linked to an E. coli outbreak more than a year ago.
The outbreak is also adding to tensions between tomato growers in Florida and Mexico. Mexican imports to the U.S. have soared since the mid-1990s, and Florida growers have lobbied for import curbs and tougher regulation of Mexican tomatoes. Last year, Mexico exported about $960 million worth of tomatoes to the U.S., accounting for almost 80% of the import market.
The rivalry between Mexico and Florida is heated in part because there is overlap in their growing seasons, which run from November to May. California, the other major U.S. player, is a springtime grower.
Jerry Wagner, director of sales and marketing for Arizona-based tomato importer Farmer's Best International, said many Mexican growers haven't been able to export their crops, and have instead flooded the Mexican market and driven down prices. One grower in Baja left his crop to rot on the vine. "He wound up walking away from a field," Mr. Wagner said.
Even when the FDA gives the all-clear, consumers may take a while to adjust. Sally Lamphier of Vermont, who dispenses gardening advice as a phone representative for retailer Gardener's Supply Co., replaced tomatoes with strawberries in a salad she recently served to friends. The home gardener hasn't ruled out one tomato supplier, however. "I'm anxious for my own to grow," she said.