I got an email last night from Washington DC asking with all the news of the recalls, how did the Salmonella get into the peanut butter in the first place and how did it get “spread” into seemingly everything else?
Well the first part is easy – its likely bird or rodent shit.
Brendan Borrell of Scientific American online actually wrote about this topic last week in an interview with Dr. Mike Doyle – “How does salmonella get into peanut butter? And can you kill it once it’s there?”
How does salmonella get into peanut butter?
Feces from some animal is a strong possibility. A leak in the roof, for example, caused one of the early outbreaks. How salmonella got into the water that was on the roof, no one knows for sure. Maybe birds, for instance, which accumulate around peanut butter processing plants.
The roasting of peanuts is the only step that will kill the salmonella. If contamination occurs after the roasting process, the game is over and salmonella is going to survive. Studies have shown that salmonella can survive for many months in peanut butter once it’s present. Fatty foods are also more protective of salmonella, so when it gets into the acid of the stomach — which is our first line of defense — it may not get destroyed. Peanut butter, being a highly fatty food, could survive better.
So, how can you keep salmonella out of peanut butter in the future?
The key is to have a rigid system in place that does not allow contamination by water or other vectors after the roasting process. Water in a peanut butter processing plant is like putting gasoline on a fire.
A couple of other things to think about from an historical perspective – this is not the first time we have had outbreaks – see the Australian and United States experiences. Also, this is not the first time someone has written about the problems of bacteria in jars of Salmonella – see "Survival of Salmonella in Peanut Butter and Peanut Butter Spread – 1990" and "Survival of Antibiotic Resistant Salmonella in Peanut Putter – 2008."
The second part, "how did it get “spread” into seemingly everything else?" is in large part answered by Peanut Corporation of America’s own press release:
The recalled peanut butter in the expanded recall is sold by PCA in bulk packaging in containers ranging in size from five to 1,700 pounds. The peanut paste is sold in sizes ranging from 35-pound containers to tanker containers.
With quantities of peanut butter in that amount being shipped all over the world, a mistake in production will have an exponential impact. We are seeing that now with more and more products being recalled.
I am sure there is more to come.