Public health officials have identified two more E. coli cases in a Minnesota outbreak that has now sickened 15 people.

The two new cases of E. coli O111 infection match the genetic fingerprint of the bacteria associated with the initial 13 cases, according to a statement issued Thursday by the Minnesota Department of Health.

The health department has conducted interviews with 14 patients thus far and concluded that 12 of those sickened ate at an Applebee’s restaurant in Minnesota between June 23 and June 29.

People sickened in the outbreak ate at restaurant locations in Bemidji, Blaine, Duluth, Monticello, New Hope, Roseville, Willmar and Woodbury, according to the health department.

“No additional details are available regarding specific ingredients, but the Minnesota Department of Agriculture continues to trace back ingredients to suppliers and points of origin looking for a common source,” the health department said in a statement.

When the outbreak was first reported, Applebee’s said it was voluntarily removing the Oriental Chicken Salad and certain ingredients from the menu at restaurants in Minnesota.

On Thursday, the restaurant company said it had voluntarily changed suppliers in order to reintroduce its Oriental Chicken Salad, along with green cabbage, shredded carrots, almonds and rice noodles to all items across the menu in Minnesota.

In a statement, the company added: “Applebee’s restaurants outside of Minnesota continue to operate with an unmodified menu.”

The health department first reported the illnesses Monday, saying all patients either had recovered or were recovering. Among the 13 patients first linked to the outbreak, four had to be hospitalized, the health department said on Monday.

Health officials said the type of E. coli that has been sickening people typically causes symptoms including stomach cramps and diarrhea, often with bloody stools but only a low-grade or no fever. People usually become ill two to five days after exposure, public health officials say, although the period can range from one to at least eight days.

Most people recover in five to 10 days.

Christopher Snowbeck can be reached at 651-228-5479. Follow him at www.twitter.com/chrissnowbeck.