By James Andrews | Feb 06, 2012
On Monday, in response to a Freedom of Information Act request from Food Safety News, the Michigan Department of Community Health released documents again naming Taco Bell as the mystery Mexican-style fast food chain linked to an outbreak of Salmonella infection from October and November 2011.
Michigan has become the second state to release documents implicating Taco Bell as the restaurant likely involved in the 10-state outbreak, first reported by the Centers for Disease Control and Prevention (CDC) on January 19. The CDC's summary outbreak report referred to the restaurant only as "Restaurant Chain A" and linked it to a cluster of Salmonella enteritidis infection that had sickened at least 68 individuals.
The document provided by the Michigan health department summarizes statistics from a case-control study comparing outbreak victims with a control group. In interviews, 29 out of 48 victims (62 percent) reported eating at Taco Bell during the outbreak window, versus 17 out of 103 respondents (17 percent) from a general population control group taken from the ten states involved in the outbreak.
The investigation compared those numbers against other fast food chains, none of which received the large disparity shown in the Taco Bell comparisons. Statistically, the study estimated an odds ratio of 9.24 to 1 that Taco Bell distributed the food contaminated with Salmonella enteritidis.
CDC investigators believe the illnesses resulted from an ingredient distributed by Taco Bell that was contaminated before reaching restaurants, although the investigation could not pinpoint a single suspect ingredient. Of the victims who ate at Taco Bell, 94 percent reported eating ground beef, while 90 percent ate lettuce and 77 percent ate cheese.
University of Minnesota environmental health professor Craig Hedberg, Ph.D., said that the document's data show a "reasonably strong" association between Taco Bell and the illnesses.
"Elevated odds ratios and confidence intervals such as these do not prove causation, but would certainly support the hypothesis that the contaminated food item was distributed by Taco Bell to its customers," Hedberg said.
Michigan reported one illness associated with the outbreak, though an epidemiologist at the Michigan Department of Community Health said the victim had not eaten at a Taco Bell during the outbreak window. Food Safety News could not confirm whether the victim had been traveling when he or she contracted Salmonella enteritidis.
The mystery behind the identity of "Restaurant Chain A" prompted some public health experts and consumers to question the transparency policies of the agencies involved in the investigation. In a response to inquiries about the Food and Drug Administration's transparency policy in such outbreaks, the FDA issued this response:
"FDA strives to provide reliable information and be as transparent and proactive as possible, particularly when there is an issue that threatens the public health," the statement read. "In situations where there are current illnesses associated with a specific food manufactured by a specific firm, or contaminated foods are distributed without known illnesses, FDA will continue to issue health advisories and press releases, as needed, to provide consumers with specific information so they may take steps to decrease their risk of illness and avoid further exposures."
"We will also continue to work with CDC and State health officials to provide support during their investigations," it added. "We are currently re-examining our practices and policies to ensure they will provide as much transparency as possible while adhering to laws and regulations."
On February 1, Food Safety News received documents from the Oklahoma State Department of Health naming Taco Bell as "Restaurant Chain A," providing the first confirmation of the restaurant's identity. With 16 confirmed illnesses, Oklahoma had the second greatest number of outbreak-related cases behind Texas, which had 43.
Following the release of the CDC's summary report on January 19, Food Safety News sent public records requests to the CDC, the FDA and the 10 state health departments involved in the outbreak, asking health officials for the name of the fast food chain and the locations of the three restaurants where more than one victim ate.
The 10 states involved in the outbreak were: Texas (43 illnesses), Oklahoma (16), Kansas (2), Iowa (1), Michigan (1), Missouri (1), Nebraska (1), New Mexico (1), Ohio (1), and Tennessee (1).
The state health departments in Nebraska and Texas have cited confidentiality for their denials of the records request. Iowa and Ohio said they did not have information on the identity of the restaurant, while the remaining state health departments have not yet responded to records requests and phone calls. The CDC has also yet to respond.
For more than a week, Food Safety News has placed multiple phone calls to Taco Bell's public relations division asking for additional information on how the restaurant chain responded to the outbreak. After repeated promises to respond, Taco Bell has still not returned any calls.
On Monday morning, a Taco Bell representative said the company is busy responding to many inquiries, but would put a priority on responding to Food Safety News.