INDIANAPOLIS -- At least one person became seriously ill after eating cheese that was sold door-to-door on Indianapolis' west side recently, the Marion County Health Department said.

The health department said it became aware Tuesday that someone sold unpasteurized soft white cheese in the area of 38th Street and Georgetown Road, as well as near 38th Street and Moeller Road. Officials are worried that others might buy the product.

The cheese was contaminated with a bacteria called listeria. The bacteria is commonly found in soil and water, but it can become dangerous when it grows on raw foods like uncooked meats, vegetables and soft cheeses, Call 6 for Help's Rafael Sanchez reported.

Symptoms of listeria infection can be as mild as nausea, but at its worst, the bacteria can cause a pregnant woman to lose her child.

Experts said that it takes at least three weeks before someone who eats something contaminated with listeria to notice symptoms.

"If something tastes bad, if it's spoiled, we tend not to eat it. We avoid it," said Dr. Crystal Jones, medical director of acute diseases for the Marion County Health Department. "Listeria can be in something that tastes perfectly good. We just don't know it, and if we're in one of those at-risk populations, it can become a very serious thing."

People who sell food door-to-door must have a food permit. Consumers can check if permits are valid by calling the Marion County Health Department at 317-221-2222.