Ogle County health officials are investigating three confirmed cases of salmonella found in people at the Rochelle Foods Inc. meat-packaging plant.

In addition to the confirmed cases, officials also have sent 15 stool samples to a state lab for testing. Those samples came from people who had flu-like symptoms or people who had contact with the confirmed cases.

The source of the outbreak is not known and further testing is required. Officials with Hormel, which owns the Rochelle plant, said the plant did not have to be closed and none of the meat was contaminated. Nearly 800 people work at the plant.