OAK BROOK, Ill.-- McDonald's says it has stopped serving sliced tomatoes in its restaurants over concerns about Salmonella food poisoning linked to uncooked tomatoes.

Proud says McDonald's will continue to serve grape tomatoes in its salads because no problems have been linked to that variety.

The source of the tomatoes responsible for the illnesses in at least 16 states has not been pinpointed. The Centers for Disease Control and Prevention has said at least 23 people have been hospitalized, and no deaths have been reported.