Of Eight Multistate Salmonella Outbreaks So Far This Year, Was This One Different?

Salmonella on Eggs

A total of 634 persons infected with seven outbreak strains of Salmonella Heidelberg were reported from 29 states and Puerto Rico from March 1, 2013 to July 11, 2014.


The first seven multistate outbreaks of Salmonella all began the same way. State health departments and the U.S. Centers for Disease Control and Prevention (CDC) began investigating human infections reported up the chain after the sickened individuals began showing up at doctor’s offices and medical clinics.


By investigating those reports, state and federal health officials were able to trace the human illnesses to their sources, including raw cashew cheese, Tyson chicken, pet bearded dragons, live poultry, frozen feeder rodents, organic sprouted chia powder, and even a microbiological laboratory.


That’s usually the way it works. People get sick. The illnesses are connected to a specific food. The product is traced back to the processing plant that made it.




But then there was the eighth multistate outbreak for Salmonella this year. At this point, it does not involve a large event. Just four people sickened by Salmonella Braenderup in four states when CDC announced it on Aug. 21.


It’s the outbreak associated with the nSpired Natural Foods Inc. recall of various conventional and organic brands of almond and peanut butter, including Arrowhead Mills, MaraNatha, Trader Joe’s, Whole Foods, Safeway and Kroger.


What was unusual about this outbreak was that it did not start with sick people going to the doctor. Instead, this Salmonella outbreak was discovered through FDA’s routine inspection of the nSpired Natural Foods plant located in Ashland, OR.


As they often do, FDA inspectors took environmental samples and subjected the isolates of the bacteria they found to both pulsed-field gel electrophoresis (PFGE) and whole genome sequencing. PFGE generated the DNA “fingerprinting” of the Salmonella bacteria. Genome sequencing identified the strain.


Then public health officials went hunting for people with illnesses that the PFGE and whole genome sequencing could tie to the bacteria found in the Ashland facility. Matches were made using the PulseNet system, and all four of those sickened reported eating either almond or peanut butter made by nSpired.




Is this example of first finding the bacteria in a food plant and then going out and seeing if anyone was sickened new and different? Is it the product of new law (Food Safety Modernization Act) with a focus on prevention? Or are the new technologies, such as complete genome sequencing, just moving from the research laboratory to the field?


Roy Costa, owner of Florida’s Environ Health Associates Inc., told Food Safety News that the nSpired investigation looks to be “a new twist on the use of such information, and the advanced molecular techniques is what made this possible. This is good for public health.”


“My thought is that only cases presenting with severe symptoms will have clinical isolates, and not all states will have the capacity to capture this information for the reporting system,” he added. “So when this turns up a hit, I suspect the outbreak will usually be much larger than four persons. Case findings now will probably intensify, so more cases will likely be identified.”




Costa said he is not sure if this amounts to prevention or just better use of the testing and surveillance systems that public health has relied upon for some time.


“Prevention would have come about if the firm (nSpired) had done the tests and found the agent before shipping contaminated products,” he said. “But, again, this is overall good for public health, just a little late.”


Dr. David Acheson, the former FDA associate commissioner for foods who now heads The Acheson Group, said this type of investigation was being done when he was in government and therefore cannot really be called new and is “not actually related to the FSMA.”


“But,” Acheson noted, “I would predict we will see more and more in the future.”




By Dan Flynn
Food Safety News