It’s probably no comfort to tomato growers who lost their crop that year, but the team that investigated the 2008 Salmonella Saintpaul outbreak has stepped up with an explanation on why there was not more precision in naming the source of the pathogen–they say it was complicated.
Writing in the New England Journal of Medicine, the Centers for Disease Control (CDC) outbreak team involved in the epidemiological investigation into the 1,500 cases of the outbreak strain of Salmonella enterica Saintpaul said their inquiry was really a series of investigations.
Raw tomatoes were implicated early on, but “subsequent epidemiologic and microbiologic evidence implicated jalapeno and Serrano peppers,” according to the journal article.
Acting on the early information, the U.S. Food and Drug Administration (FDA) warned consumers not to eat tomatoes, just as many spring and early summer crops were ready for market.
The nationwide investigation that followed was really a series of separate studies and probes into as many as nine restaurant clusters in a half dozen states.
“Raw tomatoes were an ingredient in an implicated item in three clusters,” the journal article says. “The outbreak strain was identified in jalapeno peppers collected in Texas and in agricultural water and Serrano peppers on a Mexican farm. Tomato tracebacks did not converge on a single source.”
CDC first learned about the Salmonella Saintpaul outbreak on May 22, 2008 when it was notified by the New Mexico Department of Health about 19 cases of Salmonella infection.
It would lead to weeks of frustrating work. The first studies focused on the New Mexico, Texas, and the Navajo Nation and nationally in 29 states to collect pattern of eating at Mexican style restaurants.
All the while the outbreak was getting more serious, with 21 percent of those infected requiring hospital treatment and two deaths. And a month after the erroneous tomato warning, FDA issued one for peppers.
The nine restaurant clusters were in such far flung areas as East Texas, New York City, Central Texas, North Texas, Wichita Falls, TX, Charlotte, NC, Roseville, MN, Little Rock, AR, and Jefferson County, MO.
Jalapeno peppers were implicated at through ingredient level analysis in the North Texas, Wichita Falls, and Roseville, MN restaurant clusters. The others did not turn up anything useful.
The outbreak team says many Salmonella illnesses are not confirmed by culture, making it likely that there were many more victims of the 2008 outbreak than were included in the count.
“The results of multiple investigations indicate that jalapeno peppers were the major vehicle for transmission and serrano peppers were also a vehicle,” the journal article says.
“These findings include epidemiologic associations between illnesses and consumption of hot peppers, the convergence of tracebacks to a single farm that grew both types of peppers but not tomatoes, and the isolation of the outbreak strain from agricultural water and Serrano peppers collected off that (Mexican) farm.”
In a response to the CDC report, “CDC Study Vindicates Tomatoes …,” the United Fresh produce industry group expressed some lingering resentment but also struck a conciliatory note.
“By prematurely jumping to the conclusion that tomatoes were causing the outbreak, officials may have unwittingly allowed the outbreak to continue,” said United Fresh president and CEO Tom Stenzel in the statement.
Stenzel added, “We credit the CDC and Food and Drug Administration now for reporting these findings, as an important lesson to be learned in outbreak investigations.” In the event of some future outbreak, he said, ” … we stand ready to work with local, state and federal officials to bring the most rapid identification, traceback and removal of a product from the marketplace.”