Correction: CHICAGO (AP) — In a June 9 story about an outbreak of salmonella linked to tomatoes at chain restaurants, The Associated Press erroneously described the policy of McDonald's Corp., which has stopped using sliced tomatoes as a precaution.

McDonald's said it will return sliced tomatoes to its menus based on guidance from the federal Food and Drug Administration and when the company is sure it has an adequate supply of tomatoes that meet its food safety and quality standards. McDonald's did not say it would withhold tomatoes until the source of the bacterial infection is known.

CHICAGO — McDonald's, Wal-Mart and other nationwide U.S. chains have halted sales of some raw tomatoes as federal health officials work to trace the source of a multistate salmonella food poisoning outbreak.

Burger King, Outback Steakhouse and Taco Bell were among other restaurants voluntarily withdrawing tomatoes from their menus, following federal recommendations that consumers avoid red plum, red Roma or round red tomatoes unless they were grown in certain states and countries.

McDonald's Corp., the world's largest hamburger chain, stopped serving sliced tomatoes on its sandwiches as a precaution until the source of the bacterial infection is known, according to a statement Monday from spokeswoman Danya Proud. McDonald's will continue serving grape tomatoes in its salads because no problems have been linked to that variety, she said.

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.

In downtown Chicago, travel agent Connie Semaitis, 49, bought a cheeseburger and a drink at a McDonald's restaurant during lunch hour Monday. She said she was happy the chain was being cautious.

"I'd rather be safe than sorry," Semaitis said.

The Food and Drug Administration warned consumers in New Mexico and Texas as early as June 3 about the outbreak. The agency expanded its warning during the weekend and chains began voluntarily removing many red plum, red Roma or round red tomatoes from their shelves in response.

Cherry tomatoes, grape tomatoes, tomatoes sold with the vine still attached and homegrown tomatoes are likely not the source of the outbreak, federal officials said.

Also not associated with the outbreak are raw Roma, red plum and round red tomatoes from Arkansas, California, Georgia, Hawaii, North Carolina, South Carolina, Tennessee, Texas, Belgium, Canada, Dominican Republic, Guatemala, Israel, Netherlands and Puerto Rico.

Salmonella is a bacteria that lives in the intestinal tracts of humans and other animals. The bacteria are usually transmitted to humans by eating foods 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.

The FDA is investigating the source of the outbreak, agency spokeswoman Kimberly Rawlings said.

"We are working hard and fast on this one and hope to have something as quickly as possible," Rawlings said Monday.

Rawlings said the FDA's "traceback" investigations typically look at similarities in illnesses reported to the CDC by state health officials. Investigators work backward to find the source of the contaminated product.

Tampa-based OSI Restaurant Partners LLC, which owns and operates eight brands including Outback Steakhouse, Carrabba's and Bonefish Grill, said it stopped serving all raw tomatoes other than grape tomatoes on Saturday evening. The company also instructed restaurants to discard salsa and other prepared foods containing raw tomatoes.

Miami-based Burger King Corp. said it had withdrawn raw round red tomatoes from most of its U.S. restaurants, as well as locations in Canada and Puerto Rico and some other Caribbean islands. Some California restaurants continued using the tomatoes because they buy from growers in states the FDA has said are not involved in the outbreak, Burger King said.

Other restaurant operators that stopped serving most tomatoes: Louisville, Ky.-based Yum Brands Inc., which owns Taco Bell, KFC, Long John Silver's and A&W All-American Food Restaurants; Orlando-based Darden Restaurants, which owns and operates six brands including Red Lobster and Olive Garden; Denver-based Chipotle Mexican Grill Inc.; and San Diego-based Garden Fresh Restaurant Corp., which operates Souplantation and Sweet Tomatoes restaurants in 15 states.

Among retailers, Wal-Mart Stores Inc. — the largest grocery seller in the U.S. — is working with federal officials to ensure affected tomatoes are pulled from Wal-Marts, Neighborhood Markets and Sam's Club warehouse stores nationwide, spokeswoman Deisha Galberth said.

Galberth said the Bentonville, Ark.-based company is modifying orders to its stores and putting an electronic block at its registers as an added safety measure to keep the recalled tomatoes from being purchased.

Jacksonville, Fla.-based Winn-Dixie Stores Inc., which operates 521 stores in five southern states, also stopped selling tomatoes involved in the FDA warning, as did Lakeland, Fla.-based Publix Super Markets Inc. Publix offered refunds to customers who bought the tomatoes before they were removed from shelves or destroyed over the weekend.

Monrovia, Calif.-based Trader Joe's, with more than 280 grocery stores in 23 states, also stopped selling the tomatoes in question and offered refunds, according to a statement from spokeswoman Alison Mochizuki.

O'Hara Township, Penn.-based Giant Eagle, which has 223 supermarkets in western Pennsylvania, West Virginia, Ohio and Maryland, said it also removed the tomatoes from store shelves during the weekend; as did Minneapolis-based SuperValu Inc., which operates Jewel, Shaw's, Cub Foods, Acme and some Albertson's stores.


On the Net:

CDC: www.cdc.gov/salmonella/saintpaul/

FDA: www.fda.gov/bbs/topics/NEWS/2008/NEW01848.html