Lettuce tapped as likely source of Taco Bell outbreak
December 13, 2006
by Joan Murphy
WASHINGTON -- After discounting green onions, health officials now believe the most likely source of the Taco Bell outbreak is lettuce, which could deal another crippling blow to an industry struggling to regain buyer and consumer confidence.
At a Dec. 13 press conference, federal health officials said they were investigating shredded lettuce, cheddar cheese and ground beef, but that case control studies and other factors pointed the finger at lettuce as the most likely source of an outbreak that has sickened at least 71 people. Tests are still underway on hundreds of more ill restaurant patrons in several states.
"The report that produce is once again implicated in a foodborne illness outbreak has a devastating impact on farmers and all companies in our industry who share the goal of providing consumers with healthy eating choices," Produce Marketing Association President Bryan Silbermann said in a statement.
Western Growers Association spokesman Tim Chelling likened the news, if it turns out to be linked to contaminated lettuce, to a "coming tsunami," just as the industry is moving quickly to write new safety guidelines. "We are proceeding with our invitation for the government to regulate us" by mandating new safety standards for leafy greens in a California marketing agreement, he said. But this latest news won't hasten those efforts because everyone is moving as fast as they can, he added.
The Taco Bell investigation has gone slowly, according to Christopher Braden, a medical epidemiologist for the Centers for Disease Control & Prevention, because investigators have had to "tease out" from patient interviews the likely culprit from a list of ingredients prepared in different combinations on the restaurant menu. But "we're fairly confident" with the information that points to shredded lettuce as the likely source, he said.
No samples of shredded lettuce or the other commodities have tested positive for the outbreak strain of E. coli O157:H7. But through patient interviews and a process of elimination, lettuce is the most likely source when compared to pasteurized cheese and pre-cooked ground beef, said Dr. Braden.
The Food & Drug Administration, which refrained from naming the lettuce supplier in the press conference, said that the focus of the traceback would be lettuce, and FDA investigators are reviewing Taco Bell records to trace the distribution and identify where the lettuce was grown. FDA is continuing to look at records for the pasteurized cheddar cheese, and the U.S. Department of Agriculture is investigating the ground beef.
When asked whether the Taco Bell strain was related to past lettuce outbreaks, a spokesman for FDA confirmed Dec. 13 that the E. coli O157:H7 strain detected in the Taco Bell patients "has not been seen previously." FDA Chief Medical Officer David Acheson said there is no indication that illnesses from the Taco Bell outbreak were "popping up in other regions" and that there have been no reports of new illnesses since Dec. 6.
Dr. Acheson said that the DNA fingerprint of E. coli O157:H7 in patients suffering from the Taco Bell outbreak does not match the Midwest outbreak at another Mexican food restaurant chain.
Lettuce suspected in Taco John outbreak But the Iowa Department of Health announced Dec. 13 that the DNA fingerprint does match in patients who ate at both Minnesota and Iowa Taco John restaurants. The investigation into that outbreak, which has sickened at least 50 in Iowa and 27 in Minnesota, is still ongoing.
The likely source of that outbreak also appears to be lettuce, although testing of food items is still underway, according to Iowa health officials.
Taco John International responded by announcing it hired a new produce vendor for 100 of its restaurants in the Midwest after news that the restaurants in question used a common vendor.
Bix Produce Chief Executive Officer Randy Wilcox said he was disappointed that Taco John chose to suspend the contract with the produce supplier, and that his company was cooperating fully with health officials, who inspected its facility this week. The St. Paul, MN-based supplier has provided information on cilantro and specific information on the production of more than 12,000 cases of shredded lettuce produced between Nov. 11 and Dec. 2, 30 percent of which was delivered to the Mexican restaurant chain.
Along with ongoing safety procedures, Mr. Wilcox said that the company had "begun a series of refresher meetings with all production and distribution employees to remind them of all good manufacturing practices currently in place." He added, "We also will take any additional measures necessary to preserve our customers' confidence in the safety and wholesomeness of the produce they offer to consumers."
PMA's Kathy Means said that the produce industry has responded to food safety concerns through teaching growers about the revised commodity specific guidance document and pursuing a marketing agreement with new food safety standards for California producers, which the industry hopes to wrap up by next spring.
The industry also is exploring a federal marketing agreement -- a long-term effort -- that could integrate food safety in buyer contracts for the country's crops. PMA plans to spend $1 million on the issue this year, along with another $250,000 from WGA.
The University of California's Trevor Suslow said that the latest news will once again "rock the confidence of buyers and consumers." He said it's imperative that new safety standards apply to all growing areas, not just leafy greens from the Salinas Valley. Growers in other parts of California, Arizona and other regions "need to pay attention" and that any new standards "must be uniformly applied across the country."
Growers are reviewing and re-evaluating food safety programs, and some, understandably so, are following "knee-jerk reactions" by stopping the use of reservoir water or instigating more testing and monitoring, he said. This all comes as California growers are dropping seed in a month or so, he said.
The issue of testing product is expected to get more complicated. Dr. Suslow said that the experience of wrongly naming green onions as the cause of the outbreak based on rapid tests points to the fact that the produce industry is becoming increasingly reliant on these tests to screen products. "We've been predicting there will be problems when people use rapid tests," said Dr. Suslow. While the rapid E. coli tests may be accurate with beef, there is the possibility of many more false positives for fresh produce, he said. In the meantime, FDA's Dr. Acheson said that the long-awaited draft report on the spinach outbreak is expected before the holidays.