Minnesota helps solve salmonella mystery

Federal authorities now think jalapeños, not tomatoes, caused the salmonella outbreak

A cluster of Salmonella saintpaul cases in Minnesota may have helped implicate jalapeño peppers grown in Mexico and distributed through Texas as the likely source of the illness that has sickened more than 1,251 and hospitalized at least 228 in 43 states and Canada.

The U.S. Food and Drug Administration and the Centers for Disease Control and Prevention held a press conference Monday to announce what was described as "a significant break" in the investigation: the discovery at the Agricola Zaragoza produce distribution center in McAllen, Texas of a jalapeño tainted with Salmonella saintpaul, a previously rare strain of the bacteria first identified in turkeys.

"The trail that led us to this facility...started with a cluster, a group that got sick in a geographic area," explained Dr. David Acheson, the FDA's associate commissioner for foods.

Acheson didn't specify where the cluster originated, but officials at the Minnesota health and agriculture departments both confirmed to City Pages that they recently traced a local Salmonella saintpaul outbreak to a jalapeño from McAllen, Texas.

"When they put this outbreak together they were focusing on the first group of cases that presented at a restaurant here in the Twin Cities that seemed like the common link, and when they looked at that exposure they identified jalapeño peppers as a statistically significant exposure in that group," says Ben Miller, the traceback coordinator for the Minnesota Department of Agriculture, who declined to name the restaurant because it's part of an ongoing investigation. "We went back through the distributor, who in turn had purchased that product from another distributor, who in turn had purchased that product from another distributor, who turned out to be down there in McAllen, Texas."

The state health department became aware of the cluster of cases the week prior to July 4, and communicated the results of its traceback around July 7.

"Right now we are actually at around 20 cases that we've confirmed that have this DNA fingerprint-type of Salmonella saintpaul," says Kirk Smith, the Foodborne, Vectorborne, and Zoonotic Disease Unit manager for the Minnesota Department of Health. "Our information probably helped FDA triangulate back on a source in Mexico, but we don't know exactly where they're working or if our stuff is linking up with data from other states."

The Minnesota cluster also appears to have played a role in the FDA's decision late last week to release a statement announcing that it was safe to eat tomatoes.

"It's the same bug," Michael Osterholm, a professor at the University of Minnesota and a leading expert in infectious disease research, said Friday. "Minnesota's data has had a great deal of influence on what the feds have looked at in terms of yesterday's call and the change in recommendation in part had a lot to do with Minnesota's data."

This has been the largest food-borne outbreak in more than a decade. The first case was discovered in New Mexico on April 10, and it was almost two months later on June 2 that the FDA issued a warning against eating raw tomatoes. By June 28, sales of tomatoes were down 17 percent and the total cost to the industry was expected to exceed $100 million.

Now it turns out all that may have been a red herring. Osterholm thinks the investigation has been bungled from the beginning.

"Ironically, really it's the FDA's case, but the CDC is the responsible party here," Osterholm says. "I think they missed the original association with peppers and have been trying ever since to justify tomatoes. I have no doubt that peppers caused it. If tomatoes played any role at all, it was minor."

Acheson acknowledged during the press conference that the investigation has not gone as planned.

"This has been one of the most complex outbreaks I personally have ever been involved in," he said. "We will look at lessons learned from this, so that next time we're in a better place."

In an email sent late Monday night, the CDC confirmed that Minnesota was one of "several clusters that were examined to identify common pathways."

"The warehouse in Texas was one such common point identified," wrote Ian Williams, chief of the CDC's OutbreakNet Team, who has been working on food poisoning outbreaks since 1994. "The investigation is continuing to further understand the pathways from farm fields to the clusters that have been identified."

It's no coincidence that Minnesota has been an important contributor to the investigation. Along with Tennessee and Oregon, Minnesota is considered among the best states at tracing outbreaks of food-borne illness.

"It's actually kind of a joke that most food-borne disease occurs in Minnesota, but it really isn't that any more occurs here, it's just that we did so much to find and document it," says Osterholm, who is the director of the Center for Infectious Disease Research and Policy at the U of M.

A good example was the October 2007 outbreak of salmonella that was eventually traced to contaminated Banquet frozen turkey and chicken potpies. Some 139 people in 30 states were sickened before Minnesota's public health investigators fingered the culprit.

"It was a huge outbreak nationwide, and it was going on for weeks and weeks and weeks, and finally the first cases occurred in Minnesota," Osterholm says. "And in three days they had cracked it, identified it, and it resulted in a national recall. It had gone for weeks and weeks and weeks elsewhere, we just hadn't had any cases yet. So Minnesota's just really well known for this. They're kind of almost a dream team of food-borne disease work."

Osterholm is scheduled to appear before Congress on July 30. "I'm gonna be one of the people testifying on what should or could have been done and needed to be," he says. "I'll be detailing a lot of this at that time, and I'll be talking about the Minnesota data at that time."

It's fitting that Minnesota may have helped investigators crack the mystery of Salmonella saintpaul, because it was here that the strain was first identified by Dr. Ben Pomeroy, a brilliant veterinarian with a passion for turkeys. In their service, he discovered many previously unknown varieties of avian salmonella, giving each new strain a name reflective of a local municipality.

"There's Salmonella minnesota, Salmonella richfield, Salmonella montevideo—so there's a whole lot of them that are all of Minnesota origin," explains Osterholm. "And that's how it happened: He discovered them in turkeys and turkey food."

Pomeroy died January 16, 2004, at age 92, and was hailed as a leading expert on the eradication and control of turkey diseases. 

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