THURSDAY, Feb. 15 (HealthDay News) -- U.S. health officials are warning consumers to discard certain jars of Peter Pan peanut butter or Great Value peanut butter because they may be contaminated with Salmonella Tennessee, a bacterium that causes food-borne illness.

The U.S. Food and Drug Administration warning is based on data from the U.S. Centers for Disease Control and Prevention, which reported 288 cases of food-borne illness in 39 states tied to both brands of peanut butter.

The affected jars have a product code -- located on the lid -- that starts with the number 2111. Both products were made by the ConAgra Inc. food company in a single plant in Sylvester, Ga., according to the FDA.

The FDA is recommending that all affected jars of Peter Pan or Great Value peanut butter purchased since May 2006 be discarded.

The outbreak appears to have started in August 2006, according to the FDA. But the CDC only recently was finally able to identify Peter Pan and Great Value peanut butter as the likely cause of the illnesses as a result of testing and recent case control studies .

How the salmonella got into peanut butter is still under investigation, Dr. Mike Lynch, a CDC epidemiologist, told the Associated Press.

New York, Pennsylvania, Virginia, Tennessee and Missouri have reported the most number of cases. About 20 percent of those sickened were hospitalized, and there were no deaths, Lynch said.

ConAgra, based in Nebraska, announced Thursday that it was recalling all varieties of Peter Pan and Great Value peanut butter with the product code 2111.

"Although none of our extensive product tests have indicated the presence of salmonella, we are taking this precautionary measure because consumer health and safety is our top priority," Chris Kircher, a ConAgra spokesman, said in a prepared statement. "We are working closely with the FDA to better understand its concerns, and we will take whatever additional measures are needed to ensure the safety, quality and wholesomeness of our products."

ConAgra officials haven't said how much peanut butter is covered in the recall. The Peter Pan brand is sold in 10 varieties, according to the company's Web site. The Great Value brand, which is also made by other companies, is a Wal-Mart brand.

As part of its investigation, the FDA has sent investigators to ConAgra's processing plant in Sylvester to review records, collect product samples and conduct tests for Salmonella Tennessee.

Meanwhile, supermarket chains across the country scrambled to pull the products off their shelves.

Stop & Shop and Shaw's, two of New England's largest grocery chains, ordered their stores to remove all the Peter Pan peanut butter, the Boston Globe reported.

In Texas, H-E-B, which operates 300 stores in the state as well as northern Mexico, removed the entire Peter Pan line from its shelves early this morning, Leslie Lockett, a spokeswoman for the company in Austin, told the AP.

And in U.S. military commissaries around the world, workers were ordered to remove all Peter Pan peanut butter jars, according to Stars and Stripes. Officials from the Defense Commissary Agency, which provides groceries for the military, sent out the order on Thursday morning, the newspaper reported.

Symptoms of salmonella include fever, diarrhea and abdominal cramps. Salmonella can cause life-threatening infections in people in poor health or who have weakened immune systems.

Any such illnesses should be reported to state or local health authorities, the FDA said.

This outbreak follows major food-borne illness scares in 2006 involving spinach, tomatoes and iceberg lettuce.

One expert said he was not surprised that such outbreaks continue to plague U.S. consumers.

"This is not an unusual event," said Dr. Philip Tierno, the director of clinical microbiology and immunology at New York University Medical Center and author of the The Secret Life of Germs and Protect Yourself Against Bioterrorism.

"Salmonella is a very prevalent organism," he added.

Tierno said these contamination problems arise because the FDA does not regulate the safety of produce -- and he doubts that the food industry can monitor itself.

"I think the government is moving toward making a change," he said. "Outside monitoring is the way to go."

Tierno said food poisoning strikes an estimated 80 million people in the United States each year. "Nine (thousand) to 10,000 people die annually from food poisoning," he said. "That to me is absurd in America."

In related news, it was announced Tuesday that ConAgra is also recalling more than 400,000 pounds of pasta and meatball meals that may have been underprocessed. The recall involves 36.6-ounce cartons of Banquet brand Homestyle Bakes Pasta & Meatballs in Marinara Sauce produced between Oct. 19, 2006 and Jan. 25. There have been no reports of illnesses linked to the product, the U.S. Department of Agriculture's Food Safety and Inspection Service said.