Experts Search for Source of Salmonella-Tainted Peanut Butter

FRIDAY, Feb. 16 (HealthDay News) -- The number of Americans sickened bysalmonella-tainted peanut butter rose to 290 across 39 states, the U.S. Centers for Disease Control and Prevention reported late Thursday, even as government scientists labored to detect the exact source of the contamination.

Health officials have warned consumers to discard certain jars of Peter Pan peanut butter or Great Value peanut butter that may be contaminated withSalmonellaTennessee, a rare but potentially fatal form of the food-poisoning bacteria. 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 U.S. Food and Drug Administration.

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

Howsalmonella-- which typically comes from animal feces -- got into the processed peanut butter remains a mystery. According to a report from theAssociated Press, rodents and birds sometimes make their way into peanut storage bins at the Sylvester plant, but anysalmonellawould be killed during the peanut roasting process, when temperatures exceed the 165 degrees needed to destroy the bacteria.

Peanuts are heated beyond that point once more during processing, during the step in which they are ground into a paste and mixed with other ingredients prior to being sealed into jars.

"The heating process is sufficient to kill salmonella, should it be present," Mike Doyle, director of the University of Georgia's Center for Food Safety, told theAP.

That means the only stage where the bacteria might get a foothold would be during the brief cool-down process, just before the peanut butter is sealed into individual jars. Still, "there's a lot that happens after that heat step before it's put in jars," Dr. David Acheson, chief medical officer for the FDA's Center for Food Safety and Applied Nutrition told theAP. "So there's definitely an opportunity for contamination after the roasting."

ConAgra spokesman Chris Kirchner told theAPthat his company randomly tests 60 to 80 jars of peanut butter daily at the Sylvester plant forsalmonellaand other contamination. "We've had no positive hits on that going back for years," he said. The plant was last visited by FDA inspectors in 2005, theAPsaid.

The plant has been temporarily shut down, and FDA inspectors visited Wednesday and Thursday to investigate the outbreak. Testing is also being done on jars of peanut butter in the homes of those sickened, the agency said.

The outbreak appears to have started in August 2006, according to the FDA, with the CDC reporting the highest numbers of cases in New York, Pennsylvania, Virginia, Tennessee and Missouri. About 20 percent of those sickened were hospitalized, and there have been no deaths.

According to CDC epidemiologist Dr. Mike Lynch, 85 percent of those who fell ill withSalmonellaTennessee said they had eaten peanut butter, and about a quarter said they ate it daily.

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. While company officials are mum on exactly how much peanut butter is being recalled, theAPsaid more than 974 million pounds of peanut butter are sold in the United States each year, and Peter Pan remains one of the country's top three brands. The Great Value brand, which is also made by other companies, is a Wal-Mart brand.