Twelve people in Cambridge, Boston, and possibly elsewhere in the state have been sickened by a salmonella outbreak since late June, prompting the closure of all Clover restaurants and food trucks with locations in Cambridge, Brookline, Burlington, and Boston.
Ayr Muir, chief executive of Clover, said he was informed late Friday about the salmonella outbreak in Massachusetts by state health investigators and decided to close all his operations over the weekend as a precautionary measure.
“Some of the people diagnosed with the strain they’re investigating had eaten meals at Clover,” he said, “and they told me they haven’t spoken to everyone yet.”
So far no hospitalizations or deaths have occurred from the outbreak, according to the Massachusetts Department of Public Health, and no other restaurants beyond Clover have closed their doors.
The department launched its investigation late last week.
Two Boston residents were sickened with the salmonella strain, according to the Boston Public Health Commission, which is participating in the investigation.
While Muir said he does not know for certain that Clover was responsible for these infections, he said there is “enough evidence that we might have been.”
He added that the state Health Department told him that it had not identified the source of the outbreak, whether it was from a particular ingredient, food supplier, or infected employee.
Clover staff are undergoing testing for salmonella, and surfaces in the restaurants and food trucks will be disinfected.
“We have a suspicion about one of our suppliers,” Muir said. “We learned about recent changes they made that we didn’t know about before.”
He declined to name the food supplier or the changes that raised his concerns.
He also would not comment on which dishes or ingredients sickened customers ate at his restaurants, because the investigation was not yet complete.
Infection with the salmonella bacteria can cause stomach cramps, diarrhea, fever, nausea, and sometimes vomiting, often within one to three days after consuming contaminated food.
The illness can last for several days and usually clears on its own without medical attention.
Patients are advised to rest, drink plenty of fluids, and avoid preparing food for others until their symptoms resolve.
In rare cases, salmonella infections can cause severe dehydration or other complications that require hospitalization and treatment with antibiotics.
The federal Centers for Disease Control and Prevention estimates that 42,000 Americans get sick each year from salmonella and that an estimated 400 people die from their infections.
Salmonella often resides on raw eggs, meat, and poultry and is usually killed by thorough cooking; raw produce, however, has also been linked to recent salmonella outbreaks due to contamination with animal products during harvesting or transport.
A 2012 outbreak in cantaloupes sickened more than 260 people and led to three deaths.
Muir, a graduate of Harvard and MIT, said he hesitated at first about closing his facilities and writing about the salmonella outbreak on Clover’s website.
“It just felt right to be transparent,” he said. “We take this really seriously, and I think our customers understand and appreciate that.”
He would not predict when his vegetarian establishments will reopen, but said that would not occur until the culprit has been determined by the state Health Department.