But neither the federal government nor local health officials had found a definitive link or announced any recalls as of yesterday.
The number of central Ohio cases has reached 15, and 11 of those cases are genetically linked, pointing to a common source of infection.
The cases also match two elsewhere in Ohio and nine in Michigan, where health officials have implicated ground beef but have not named a source.
Health officials here have said that the people they've interviewed ate ground beef and raw fruits and vegetables before becoming ill. But Ohio investigators are not naming a specific food source of the Escherichia coli bacteria, which live in the intestine and are spread in feces, most often via water or food.
The vice president of a New Jersey hamburger plant said that officials are exploring whether the Ohio and Michigan illnesses are linked to a recall by his company this month.
Dutch's Meat recalled 13,275 pounds of hamburger on June 8 after discovering that it might have been tainted with the sometimes-lethal bacteria. None of that meat left New Jersey, said Vice President Al Granaldi. No illnesses were connected with Dutch's products.
Dutch's gets its meat from three or four suppliers. If the strains match, it's possible that one of those companies sold him tainted meat and also distributed that meat to Ohio, Michigan and elsewhere, he said.
Granaldi would not name a meat supplier but said that one in the Midwest might be the source. "They probably distribute all over the country," he said.
Michigan investigators are looking into a possible link to the Dutch's recall, said James McCurtis, spokesman for the Michigan Department of Community Health. Neither federal health officials nor investigators in Ohio would confirm a connection.
"We're still investigating and hope to have a source next week," McCurtis said.
"We're confident that it is ground beef."
That outbreak has sickened at least 29 people in Michigan and hospitalized five people there. Six Ohioans have been hospitalized. No deaths have been linked to this outbreak.
Once illnesses in more than one state were linked, the federal Centers for Disease Control and Prevention got involved, but a spokeswoman there had little to say yesterday.
Lola Russell said she didn't know how long the investigation will take and that the CDC is just beginning to collect information.
The CDC is not a regulatory agency. The U.S. Department of Agriculture would announce any recalls. A call to a USDA spokeswoman yesterday afternoon was not returned.
The Franklin County Health Department sent a food sample to the Ohio Department of Agriculture for testing this week and expects results by the middle of next week, spokeswoman Mitzi Kline said.
Of the central Ohio cases, 10 are from Franklin County, including five in Columbus. The others are in Fairfield and Delaware counties.
E. coli infection usually causes diarrhea, which can be bloody and appears in two to eight days after infection. People who have symptoms should contact their doctors.