Salmonella’s ‘fingerprint’ could be clue to its source

Source of Article:

The Atlanta Journal-Constitution

Sunday, March 01, 2009

An unusual strain of salmonella with a distinctive “fingerprint” caused the 2007 recall of a popular brand of peanut butter made in Georgia.

Two years later that unique fingerprint is back.

• For all the latest developments on the peanut crisis and the salmonella outbreak, with an updated list of recalled items, plus background on the scare, go to the AJC's special report:

Because the Peanut Corporation of America recall involves so many different products, federal officials urge consumers to make sure items in their pantries or freezers are not on updated lists.

·                                 Go to

·                                 Call 1-800-CDC-INFO

·                                 Recall lists, background and latest headlines at peanuts

·                                 Major brands of jarred peanut butter are not in the recall

Federal and state officials have found several strains of salmonella in Peanut Corp.'s Blakely plant and its products.
Salmonella Typhimurium

·                                 One of the most common strains of salmonella causing disease in the U.S.

·                                 Bacteria with a specific genetic "fingerprint" of this strain have been found in the bodies of more than 660 people sickened in the outbreak who ate peanut products from the Blakely plant.

·                                 Colorado health officials recently identified some people in their state sickened with this strain and fingerprint who ate peanuts from Peanut Corp.'s Texas plant, which had been ground into peanut butter at a local store. This has raised questions about peanuts or products being shipped between the Georgia and Texas plants.

Salmonella Tennessee

·                                 A less common strain.

·                                 Bacteria of this strain with a specific genetic fingerprint caused an outbreak in 2006-07 that sickened people who ate peanut butter made at a ConAgra plant in Sylvester.

·                                 Recent tests by the Minnesota and Georgia agriculture departments found that same fingerprint in King Nut peanut butter made at Peanut Corp.'s Blakely plant.

·                                 Although the strain can make people sick, no illnesses linked to Peanut Corp.'s products have so far involved the Tennessee fingerprint. The CDC estimates only 3 percent of all people sickened by salmonella undergo lab tests and have results reported to the agency. "I'll bet you there are cases in the United States, they just haven't been identified," said food safety expert Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

Salmonella Anatum

·                                 Detected in samples of creamy peanut butter, peanut meal and chopped peanuts made at the Blakely plant in August and September 2008.

Salmonella strains Mbandaka and Senftenberg

·                                 Detected in swab tests inside the Blakely plant examined by the FDA in January.

Sources: AJC research, FDA inspection report

This time it’s in some peanut butter produced by the Peanut Corporation of America’s plant in Blakely. That plant — responsible for the current recall of a wide range of peanut products — is 73 miles west of ConAgra’s plant in Sylvester that had the contamination problem two years ago.

Federal investigators say the link has caught their attention as they look toward peanut hullers and possibly farms for how several strains of salmonella got into the Blakely plant.

Raw peanuts grown in Georgia may be the common source of salmonella in the two factories, food safety and industry experts said. Georgia produces 41 percent of U.S. peanuts.

ConAgra officials said raw peanuts from Georgia and north Florida most likely brought salmonella into their plant two years ago and contaminated ready-to-eat peanut butter.

The two outbreaks raise questions about whether peanut farmers need to change their agricultural practices to reduce bacteria on their crops — just as dairy farmers do with raw milk, even though it will be pasteurized to make it safe.

“Our general impression is that salmonella doesn’t start in a [manufacturing] plant. It comes in on something or with something,” said Dr. Robert Tauxe, a top food safety official at the Centers for Disease Control and Prevention in Atlanta.

“How salmonella might be introduced in a plant might include coming in on raw peanuts, wild birds perching on a roof or other things that might come into or around the plant environment,” Tauxe said.

But the Georgia Peanut Commission, which represents Georgia’s 4,535 peanut growers, and the state Department of Agriculture said that, regardless of the source of contamination, processing plants are ultimately responsible for food safety.

“It’s not a grower issue, it’s an industry issue,” said Don Koehler, the peanut commission’s executive director.

Oscar Garrison, assistant commissioner in the Agriculture Department’s consumer protection division, said food processing plants are expected to make peanuts safe with proper roasting to kill any bacteria. They also must use good sanitation practices, he said.

The department — which is responsible for inspecting food plants and promoting Georgia agriculture — is working with the U.S. Food and Drug Administration to trace how the Blakely plant and its products became contaminated.

After the outbreak was traced to the Blakely plant, inspectors found numerous sanitation problems, including salmonella on surfaces inside the plant.

The FDA is examining peanut shelling operations that supplied raw peanuts to the Blakely plant, an official with the agency said. Depending on what they find, they’ll look at farms that supplied peanuts to the shellers.

Officials with the American Peanut Shellers Association and two shelling operations in Blakely — Universal Blanchers and Birdsong Peanuts — did not respond to interview requests.

The FDA has identified several strains of disease-causing salmonella in the Blakely plant and its products. A strain called Typhimurium is the one linked to more than 660 illnesses and nine deaths across the country.

“Oftentimes these investigations are inconclusive and we can’t find the smoking peanut,” said an FDA official, who asked not to be identified because the investigation is ongoing.

But experts at the FDA and the CDC said they are intrigued by an unusual clue.

Two years ago the ConAgra plant in Sylvester launched a nationwide recall of Peter Pan peanut butter after consumers were sickened by a less common strain of the bacteria, called Salmonella Tennessee. It had a unique genetic fingerprint.

On Jan. 22, tests by the Minnesota Department of Agriculture found salmonella with that same genetic fingerprint in an unopened 5-pound container of King Nut peanut butter produced late last year at the Blakely plant. Georgia inspectors also found the salmonella fingerprint from the ConAgra outbreak in a King Nut container.

ConAgra officials concluded raw peanuts and raw peanut dust were the most likely source of the Tennessee strain of salmonella in the company’s 2006-2007 outbreak. All the peanuts came from farms within 150 miles of the ConAgra’s Sylvester plant, company spokeswoman Stephanie Childs said.

When the plant’s roof leaked and a sprinkler system malfunctioned, the company believes water activated salmonella bacteria brought in on raw peanuts and their dust, spreading contamination to peanut butter.

That conclusion prompted ConAgra to spend $33 million to redesign its operations, Childs said. Now employees work on the finished-product side of the plant or in the raw-peanut area, but not both, Childs said. ConAgra’s raw-peanut area has a separate air-handling system to keep contaminated dust away from finished peanut butter.

Despite hundreds sickened between the two outbreaks, nobody appears to know what percentage of raw U.S. peanuts are tainted with salmonella or how heavily contaminated some batches may be.

The American Peanut Council is seeking answers to those questions with a study set to begin in April; results are expected in 18 months.

Council President Patrick Archer said the peanut industry uses farming practices intended to minimize contamination, such as cleaning equipment to lessen mold and bacterial growth.

Some food safety experts questioned whether the peanut industry is aware some farming practices may increase the risk of salmonella contamination. Only one Georgia peanut farm has sought and received certification of using good agricultural practices, said Arty Schronce, a state Agriculture Department spokesman.

“My impression is the farmers really don’t have good agricultural practices,” said Michael Doyle, who has served as a consultant for ConAgra and the American Peanut Council. Doyle is director of the Center for Food Safety at the University of Georgia.

When peanuts are roasted, Doyle said, the focus may be more on achieving the right flavor rather than on safety. If salmonella is present in very large numbers, the roaster may not kill all of it, he said.

Doyle said he recently got a call from a peanut industry adviser in Georgia. “The bottom line I got from him: The farmers feel the processor is at fault and should process the salmonella out of the peanuts,” Doyle said. “They’re looking at the peanut as a commodity, rather than a food.”



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