After a months-long investigation, a salmonella outbreak that has sickened more than 400 people in 43 states has been linked to a type of peanut butter sold to institutions including schools, nursing homes, restaurants, and hospitals. Three deaths are being investigated in association with the outbreak—two in Virginia and one in Minnesota—according to news reports by the Associated Press.

King Nut, an Ohio-based company that distributes peanut butter manufactured by Peanut Corporation of America, has recalled peanut butter distributed under its King Nut and Parnell's Pride labels. Although King Nut took steps to recall the five-pound vats, the company said the products that it distributes could not be the source of all the illnesses because it delivers to only seven states (Ohio, Minnesota, Michigan, North Dakota, Arizona, Idaho and New Hampshire).

According to the Atlanta-Journal Constitution, federal investigators have conclusively linked the strain of salmonella to peanut butter manufactured by a Peanut Corporation of America facility in southwest Georgia. In a statement on its Web site, however, Peanut Corp. of America said that the finding "leaves open the possibility of cross-contamination from another source."

If this all seems confusing, it is, and it once again highlights the need for better food forensics in the U.S. The illnesses tracked in this current outbreak began between Sept. 15 and Jan. 7, with most of the people becoming sick after Oct. 1—a period of almost four months. Why has it taken that long to track down the source? (It takes about three weeks for a case to be identified, analyzed and submitted to PulseNet, a national network of public health laboratories, and nearly a month overall by the time the CDC recognizes a cluster and attempts to identify a common food source.)

As we advocated this summer, the U.S. food system needs better traceability and inspections and the Food and Drug Administration should be given mandatory recall authority. This would knit together the efforts now performed by a patchwork of state and federal agencies.

Unlike the recall of Peter Pan peanut butter two years ago, common brands of peanut butter sold in grocery stores do not appear to be associated with the current salmonella outbreak. People who think they may have become ill from eating peanut butter are advised to consult their health care providers who should, in turn, contact state or local health departments. You can also report a complaint to the FDA. Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12–72 hours after infection.  It can be particularly hazardous to the young, the elderly and those with compromised immune systems, which makes this outbreak particularly worrisome because of where the contaminated peanut butter has been distributed.  

Until the source of the widespread contamination is better understood and controlled, we suggest that you not eat peanut butter that wasn't purchased in a grocery store.

For more on the symptoms of salmonella and other food poisoning, read the 411 on foodborne illness.
You can also follow the investigation on the Web sites of the Minnesota Health Department and the FDA.