SALT LAKE CITY — Fifty-five people at a homeless shelter were treated for suspected food poisoning at local hospitals Sunday and Monday.

Medical crews arrived at the Road Home, 210 S. Rio Grande St., Sunday night after multiple reports of men, women and children with symptoms including vomiting and severe stomach pain. Ten ambulances and a bus transported the sick to various hospitals, police said.

Three children were among those treated, said Ilene Risk, Salt Lake County Health Department epidemiologist. Most of the sick were released that night after emergency room treatment. One adult was hospitalized but was released Monday afternoon.

Considering the number of people requiring medical attention and the severity of their illness, Risk said the health department only deals with cases on such a scale about every five years.

“My biggest concern with this outbreak is that we will be able to quickly identify the cause,” Risk said. “We don’t always identify the cause, but what we can do is make sure the appropriate practices are in place to prevent illness.”

Risk said many of those who fell ill ate at St. Vincent De Paul, a local soup kitchen, so health officials have been examining the kitchen. However, she said many of those who fell ill also received some sack lunches at a park, so a thorough investigation must be completed before any conclusions are made, especially since food poisoning symptoms can take several days to surface.

Danielle Stamos, spokeswoman for Catholic Community Services, said St. Vincent De Paul served nearly 550 people the same dinner Sunday night. If the illness originated from the kitchen, she questions why more people didn't get sick but said they are taking the incident seriously.

"We are very concerned about it," Stamos said. "We work diligently every day to ensure that our clients are getting healthy and safe food from our kitchens. We are inspected by the health department regularly, and we've always had such a great standing, so it's something that's very important to us."

Nicholas Rupp, communications coordinator with the Salt Lake County Health Department, said the homeless can be particularly susceptible to food-borne illness, especially since the Utah Legislature passed a law in 2014 preventing the health department from regulating some charitable groups before they're allowed to pass out food.

"We don't want to dampen people's charity," Rupp said. "We applaud people wanting to help, but we just ask that they help in the right way, which is by funneling their volunteer hours or their food through a permitted organization like St. Vincent De Paul rather than doing it on their own."

Stamos said whether the illness came from St. Vincent De Paul or from community members handing out food themselves, the case should prompt all community members, including volunteers and the homeless, to take precautions when giving or receiving food.

"A lot of people, concerned citizens, take it upon themselves to serve in the streets or at parks, and it's just a great reminder for us that we need to make sure we're not doing that and (instead contacting) agencies that are specialized in serving the homeless," Stamos said. "It's important that we follow certain protocols to ensure that people stay safe and healthy."

Stamos said the incident has been very "disappointing" to Catholic Community Services, so the organization hopes to work with the community to make sure it never happens again.

"We want to get to the bottom of it more than anyone else," she said.

Rupp said it could take several days to complete the investigation.