A salmonella outbreak on campus in late April and early May most likely resulted from food contamination by a Frist Campus Center worker who was ill, a state health investigation found.

University spokeswoman Cass Cliatt ’96 said there were 28 confirmed salmonella cases — 20 students and eight University staff members, including three food handlers. Another 42 individuals were termed “probable” cases, according to the state.

Several food items served at a Mexican food station in the Frist Gallery were linked to those who contracted the illness, said Mary Glenshaw, an Epidemic Intelligence Service officer with the CDC who is working with the state health department and who headed the investigation.

Those who developed gastrointestinal illness ate at Frist between April 18 and May 2, Glenshaw said, with symptoms — including diarrhea, abdominal cramps, fever, nausea, and/or vomiting — showing up from April 20 to May 7. She said three individuals who became sick received hospital emergency-room treatment, while eight students spent a night at McCosh Health Center because they had become dehydrated.

On May 3 the University shut down the Mexican and salad-bar food areas at Frist, two of several food stations that are part of the Frist Gallery. The two food stations reopened May 19.

Dining Services, which operates the Frist eating areas, is putting into effect new training that emphasizes the importance of hand-washing and sanitation, Cliatt said.