Spokeswoman Danya Proud said Monday the world's largest hamburger chain has stopped serving sliced tomatoes on all of its sandwiches in the United States as a precaution until the source of the salmonella is known.
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.
Investigations by the Texas and New Mexico Departments of Health and the U.S. Indian Health Service have tied 56 cases in Texas and 55 in New Mexico to raw, uncooked, tomatoes.
"We're seeing a steady increase," Deborah Busemeyer, New Mexico Department of Health communications director, said Saturday.
An additional 50 people have been sickened by the same Salmonella "Saintpaul" infection in Arizona, California, Colorado, Connecticut, Idaho, Illinois, Indiana, Kansas, Oklahoma, Oregon, Utah, Virginia, Washington and Wisconsin, the federal Centers for Disease Control and Prevention reported.
Investigators are trying to determine if raw tomatoes also are responsible for the illnesses in those states, said Arleen Porcell, a CDC spokeswoman.
In response to the problem, the FDA has issued a tomato warning to consumers in all 50 states, reports CBS News correspondent Nancy Cordes.
The rarity of the Saintpaul strain and the number of illnesses "suggest that implicated tomatoes are distributed throughout the country," she said.
Interviews conducted with 73 people found the illnesses began between April 16 and May 27, Porcell said.
Salmonella is a bacteria that lives in the intestinal tracts of humans and other animals. It usually is transmitted to humans by eating food contaminated with animal feces.
Most infected people suffer fever, diarrhea and abdominal cramps starting 12 to 72 hours after infection. The illness tends to last four to seven days. Many people recover without treatment, but severe infection and death is possible.
Early Show medical correspondent Dr. Emily Senay offered insight on the situation. To see the interview, click on the arrow in the image below: