The Salt Lake County health department is interviewing everyone who got sick Sunday night to determine what and where they ate in the previous two days, agency epidemiologist Ilene Risk said. Only one person remained hospitalized Monday.
Early indications point to a food-handling error, not something malicious, Risk said.
Several charity and non-profit outlets near the shelter provide food to the homeless, including one that gives out sack lunches, Risk said.
None of them have been shut down, and Risk said she doesn't expect any to lose its license or face any legal consequence. County health officials will work with those organizations once they determine the outbreak's cause, so they can prevent it from happening again.
"It's very sad that that many people were this ill to seek care at an emergency department; however, people get foodborne illness all the time," Risk said. "Our job is to make sure we understand why they got it and to prevent from occurring."
Paramedics responded to the Road Home shelter after receiving reports of multiple people vomiting, Salt Lake City Fire Department spokesman Jasen Asay said. A bus was brought in to transport people to hospitals for treatment, Asay said.
Hundreds were in the shelter at the time. Emergency officials took 48 people to hospitals, and seven others went on their own. Three of those who got sick were children, but Risk declined to give their ages.
The hospitalized person is expected to be released soon, she added.
Those who got sick were staying at the shelter, but the facility did not serve any meals over the weekend, said Celeste Eggert, the shelter's development director. Many of those staying at the shelter eat at nearby kitchens and facilities, Eggert said.
Associated Press writer Michelle L. Price contributed to this report.