I don’t like peanut butter. Never have. Hate’s a strong word, but I hate peanut butter. Just another food I don’t like – like sprouts and green onions — that will reduce my risk of contracting foodborne illness.

And if I was institutionalized, the last thing I would want is peanut butter. Unless I was really old or pregnant, then I wouldn’t want deli meats either (that listeria thing).

The U.S. Centers for Disease Control, which is apparently getting a new boss, reported Friday that 399 persons have become infected with the same outbreak strain of Salmonella Typhimurium in 42 states. And, as the startribune.com of Minnesota reports, Minnesota disease investigators once again may have solved the riddle of a nation-wide salmonella outbreak. This time the culprit is peanut butter.

Kirk Smith, supervisor of foodborne diseases at the state health department, said that the clue in this outbreak was that many of the Minnesotans who became ill had eaten in institutional settings. That included nursing homes, schools, and colleges, he said.

"What they had in common was this brand of peanut butter," he said. "That was enough."

Officials from the Minnesota Department of Agriculture (MDA) and the Minnesota Department of Health (MDH) issued a product advisory after MDA’s preliminary laboratory testing indicated the presence of Salmonella bacteria in a 5-pound container of King Nut brand creamy peanut butter.

I want to say I work for King Nut. Or the other way around. But until that link is firmed up, here’s an op-ed from the last peanut butter outbreak two years ago, involving ConAgra’s Peter Pan brand peanut butter, which was eventually linked to at least 625 salmonella cases in 47 states. I hate peanut butter as much as jazz (see video below).

PB & J, the new spinach
Feb. 16/07

Contrary to the protestations of Shaquille O’Neal during a game of Scattergories on Curb Your Enthusiasm, peanut butter is not often thought of as a dairy product (peanut BUT-TER he winks at Larry David).

Peanut butter is also not often thought of as a source of salmonella.

As Katie Kuba, 23, said yesterday while shopping in Dorchester, MA, "It’s alarming that it’s something like peanut butter. You wouldn’t think peanut butter, it’s mostly spinach."

As Americans sort through their pantries to see if Peter Pan or Great Value is amongst the three-or-four half-empty jars of peanut butter most families maintain, many, including the almost 300 confirmed sick, may be wondering, how does salmonella get into peanut butter?

Salmonella commonly originates in the feces of birds and animals, and could be introduced at numerous points in the peanut butter-making process, but are normally killed during the peanut roasting process, and again with heat during the production of peanut butter.

But it has happened before.

Beginning in April 1996, some 500 people across Australia were stricken with Salmonella that had made its way into peanut butter.

At first, investigators focused on chicken; that chickens carry Salmonella has been worn into the public’s food safety conscious for decades. But as cases of Salmonella increased across the country and after questioning the sick and the vomiting, an unlikely food source emerged: peanut butter.

In the 1996 Australia outbreak, researchers first found the same genetic stain of Salmonella in peanut butter from the homes of some of the sick (unlike fresh produce, the long shelf-life of peanut butter provides an advantage for disease detectives). Because the manufacturer retained samples for shelf-life tests, the peanut butter was found to contain the same strain of Salmonella, as did the roasted peanuts from a single supplier.

After six months of investigation, Australian researchers came up with a theory: the roasting company had moved and separated the roasted peanuts with an auger, a drill-like machine with a spiraling blade that could lift piles of peanuts, that had been contaminated with mouse feces.

Peter Wood, senior lecturer in microbiology at Queensland, University of Technology, Brisbane, was quoted as telling the American Society of Microbiology in 1999 that, "The auger was only used four times because it proved not to be as time-saving as first thought," and the machine had been kept in the company tool yard. During that time, eastern Australia was in the throes of a plague of mice. The rodents nested everywhere, including the tool yard, where their droppings contaminated the auger. When the auger was brought in to the plant, it was washed down but Wood said it was not sanitized before it was used on Jan. 10, 1996. Salmonella from the auger mixed with the peanuts, and contaminated the system.

Salmonella is commonly associated with the feces of birds and animals, has been found to survive in soil in almond orchards, and could be introduced at a multitude of stages in the peanut butter-making process. Although processing normally eliminates contamination, several studies following the 1996 Australian outbreak have revealed that the high fat content of peanut butter can actually protect individual bacteria during the heating process.

Similarly, in 2006, Cadbury in the U.K. recalled 1 million candy bars after tentative links with Salmonella cases stretching over 6 months. A leaky pipe in the production facility may have been the cause. Maintenance and sanitation, two departments integral in food safety system success, appear to have failed in both outbreaks.

An estimated 974 million pounds of peanut butter is sold each year and a jar of peanut butter is sold every second in the U.S. From carrot juice to spinach to tomatoes, the sources of foodborne illness continue to surprise. The best prevention is constant vigilance.