Cramps, diarrhea, vomiting…. Interviewing people about their food poisoning symptoms isn't a glamorous job. Yet, the investigative work of a group of public health graduate students who work for the Minnesota Department of Health (MDH) has helped find the sources of the country's two most recent major salmonella outbreaks, in peanuts earlier this year and in jalapeño peppers (previously blamed on tomatoes) in 2008. Dubbed "Team Diarrhea," or "Team D," the students' work has played a major role in solving cases that had kept health officials in other states stumped for months and sickened thousands of people.

National food-poisoning outbreaks such as that of the contaminated peanuts are relatively infrequent—four or five annually. Yet, every year an estimated 76 million cases of food-borne illness and 5,000 associated deaths occur in the United States, according to the U.S. Centers for Disease Control (CDC). Rapid investigation is critical to detect an outbreak, determine its source, minimize continuing exposure to the pathogen, and, ideally, prevent such occurrences in the future.

Like telemarketers, Team D works in a giant cubicle, armed with telephone headsets and questionnaires geared to specific pathogens. The team consists of six to eight students from the University of Minnesota School of Public Health. They are intensively trained and work an average of 20 hours per week with close oversight from MDH epidemiologists on more than a thousand cases each year. That means talking to a lot of people who may have simply mishandled raw chicken or eaten spoiled food at a picnic. They're paid less than their full-time professional counterparts in the health department, but these students gain critical public health experience and "they stretch our resources a ton," says Kirk Smith, supervisor of the MDH's Food-borne, Vector-borne, and Zoonotic Diseases Unit.

By law, Minnesota doctors must submit stool culture bacteria from suspected cases of any enteric (intestinal) illness—such as Escherichia Coli (E. coli), salmonella, shigella, and a host of others—to the MDH laboratory. There, the pathogen is confirmed and "fingerprinted" by pulsed-field gel electrophoresis, which distinguishes strains of organisms at the DNA level. "You could get 10 cases of salmonella in a week and without DNA, you couldn't know if they're unrelated or all part of one outbreak," Smith says. The lab relays positively identified cases to the CDC and to Team D, whose members immediately talk to each victim.

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