E. coli O157:H7 has literally gone nuts! The “hamburger disease” makes an appearance in soy nut butter.


Let’s start out by doing a flashback to this point in time 35 years ago. E.T. just wanted to “phone home,” and Michael Jackson was a zombie that was dancing the “Thriller,” but on the food safety front, two very important foodborne illness outbreaks were occurring in Oregon and Michigan. From February to May 1982, 47 individuals, who had consumed undercooked ground beef at a particular restaurant chain, became infected with Escherichia coli O157:H7, a serotype of E. coli which had been rarely observed prior to that point in time. Eleven years later in 1993, E. coli O157:H7 struck again as the etiologic agent of a multi-state outbreak of foodborne illness that affected an estimated 732 individuals. The illnesses in these individuals, most of whom were under the age of 10, were also linked to consumption of undercooked ground beef. Those who know, also know that this outbreak also forever changed the landscape of food safety in the United States. Consequently, E. coli O157:H7 quickly earned itself the moniker “hamburger disease” due to its association with these foodborne illness outbreaks related to ground beef.

However, in more recent years, the food safety community has come to realize that E. coli O157:H7 is not just a “hamburger disease.” In fact, in 2006 it also became a “leafy green disease,” and in 2009 it became a “cookie dough disease.” Now, in 2017, it has become a “soy nut butter disease.” The I.M. Healthy brand SoyNut Butter outbreak has been ongoing since early January 2017, and as of today, April 10, 2017, there are 29 cases of foodborne illness, 12 hospitalizations, and nine cases of hemolytic uremic syndrome (HUS) that have been linked to the outbreak. The outbreak is currently spanning 12 states, and since March 7, The SoyNut Butter Company has had a recall in place on all of its varieties of I.M Healthy SoyNut Butters and all varieties of its I.M. Healthy Granola products. This recall was expanded on March 10, 2017 to include Dixie Diner’s Club brand Carb Not Beanit Butter. Furthermore, Lifestyle Yogurt Peanut Crunch Bars were recalled on March 23 because they contain a recalled ingredient. Laboratory testing has obtained the outbreak strains of E. coli O157:H7 in the I.M. Healthy brand SoyNut Butter collected from the homes of ill people and from retail locations, establishing a strong epidemiological link to these products as the source of the outbreak. One of the biggest concerns is the availability of the product to children. The company purports that over 2 million children eat their product every month.

So, the question that is now undoubtedly on people’s minds is “how did the ‘hamburger disease’ become a ‘soy nut butter disease?’” People were asking this very same question in 2009 when the “hamburger disease” became the “cookie dough disease.” Although it was speculated that flour was the source of the E. coli O157:H7 contamination in the pre-packaged cookie dough, upon conclusion of the investigation into the outbreak, no one source of the contaminant was definitively identified. Either way, the source of the contaminant was not one that had ever been documented before. The same is true for this current soy nut butter outbreak. The main components of the product are roasted soybeans, naturally pressed soybean oil, palm oil, soy lecithin, and salt. To my knowledge, these have never been linked to an outbreak of illness due to E. coli O157:H7.

This now begs the question, “what food products should be considered to be ‘high risk’ for E. coli O157:H7?” I would say that we are learning more and more as we go along. Low water activity foods were previously thought to be “immune” from foodborne bacterial pathogens from the Enterobacteriaceae family. Salmonella, which was historically considered to be a poultry product pathogen, and E. coli non-O157 STECs, which were thought to be related to beef products, were not considered to be “high risk” pathogens for low water activity foods. However, with outbreaks of foodborne illness occurring due to Salmonella in peanut butter, due to E. coli O26 and E. coli O121 in flour, and now due to E. coli O157:H7 in soy nut butter, we are now gathering more and more evidence that low water activity products are at risk for contamination and transmission of illness with these particular bacteria.

So, what should we do now? Well, in any food safety system it is essential to conduct a hazard analysis to properly identify any hazards that can be introduced into your system, and then implement control measures to mitigate those hazards. Thus, in principle, one should react in the same way according to the fundamental food principles that they have been taught. The only difference is that now one may need to adjust their risk levels for certain biological hazards with regard to certain ingredients. The overall approach thereafter will remain the same. As the research catches up, one will soon be supplied with better information on how this type of hazard can be mitigated with certain controls (e.g. thermal treatments, chemical treatments, non-thermal treatments etc.), but in the meantime it may be sensible for suppliers of these types of products to get ahead of the curve and conduct their own process validation studies with third party laboratories (such as FSNS) or academic institutions in order to determine whether their processes are indeed controlling these hazards. These laboratories have resources at your disposal that can help you through the entire course of validating your process, and, best of all, they are eager to help! This will also help ensure that you have the proper documentation in place when the FDA comes knocking on your door in the next few months, if they have not already done so.

In another 35 years we may be looking back at how the Beauty showed the Beast true love (in computer animation), how Bruno Mars held everyone spellbound with his “24K Magic,” and how the soy nut butter outbreak led food microbiologists to a breakthrough with regard to the control of E. coli O157:H7 in low water activity foods. However, until then, we all need to stay vigilant about the risk that this pathogen poses for low water activity foods, recognize that it may pose a risk to our products, and take measures to validate that our processes are able to control its presence. Overall, this is the most prudent approach to take, and it will surely help you sleep better at night.

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