An ongoing investigation of an E. coli outbreak near Louisville, Ky., has cleared the cafeteria initially suspected of being a source.

At least ten people, including seven schoolchildren, fell ill last month after being contaminated with E. coli in southern Indiana town Floyds Knobs, about 15 miles northwest of Louisville, Kentucky.

According to the Associated Press, the first infection was recorded on September 21. This, as well as the following cases, seemed to be connected to the cafeteria of Galena Elementary School in Floyds Knobs.

Officials now say that the outbreak is not connected to any of the school cafeteria’s food not is it related to last week’s massive recall of Topps Meat Company frozen ground beef products, reports the AP. No Topps frozen hamburgers were served in the cafeteria.

According to the school district, at least three of the cases seem to have appeared due to exposure to a sick family member. One school representative called the situation a type of “person-to-person transmission.”

The AP reports that Bill Briscoe, the district's assistant to the superintendent for administration and operations, wrote in an online update Wednesday: “This type of person-to-person transmission occurs when an ill person does not wash hands thoroughly after using the bathroom and may have been a contributing factor for illness transmission among the students at the school.”

Galena Elementary has remained open since the first infection in late September and has been cleaned regularly, officials said. While there are ten confirmed cases, health officials were still waiting on lab results for some other suspected infections.

Topps Meat Company of Elizabeth, New Jersey issued a massive recall last week of more than 20 million pounds of frozen hamburgers because of possible E. coli contamination. Two dozen people may be ill after consuming bacteria-tainted Topps frozen burgers, the Centers for Disease Control and Prevention confirmed last Wednesday.

As to the Galena case, the investigation continues in search of a definitive conclusion.

Symptoms of E. coli contamination are bloody diarrhea, vomiting, and abdominal pains. It can lead to kidney failure. Persons most at risk in case of contamination with E. coli from the beef are children and the elderly. The bacteria can be spread by person-to-person contact.