The Chicago Tribune reports a recent outbreak of salmonella sickened students at five schools in the Chicago suburbs, and health officials have focused their investigation on a commercial kitchen in Wheeling that prepares lunches for the schools.

The children, ages 7 to 14, have recovered, and the outbreak appears to be over, officials said Friday.

The illnesses came to light at a school in southwestern Lake County, where one student became sick Sept. 20 and two others fell ill in the following days. One of those students was hospitalized for four days, but all have recovered, Lake County Health Department epidemiologist Victor Plotkin said.

Five additional cases were found at four schools in northern Cook County, but none required hospitalization, Cook County Department of Public Health spokeswoman Amy Poore said.

Health officials say they have traced the likely source to the kitchen of a vendor for the schools, OrganicLife in Wheeling, Poore said. Letters were sent to about 100 schools served by the kitchen, alerting them to the outbreak and asking them to look out for symptoms, which typically include diarrhea, stomach cramps and fever.

As of Monday, Poore said, OrganicLife was allowed to provide only hot or prepackaged foods pending an inspection of its kitchen and until all food workers are

OrganicLife markets itself as “the leading provider of healthy lunches in the state of Illinois.” Its website states that it serves more than 1 million meals a month at schools, day cares and universities.

Earlier this month, students at a South Side high school became ill after eating school lunches that had been contaminated with rat droppings.

I have no idea if the outbreaks are related, but rat droppings would be natural.