In Canada, August signifies the arrival of the agricultural exhibition. Cities from across the nation celebrate the end of summer with games, concerts, midway rides and, of course, a diverse choice of foods ranging from corn on the cob to cotton candy. Amid the annual offerings, one particular item usually stands out as a fan favorite for its uniqueness and quirkiness. This, in turn, leads to long lineups, media hype, and, in the social-media age, photos and updates from those choosing and eating the selection. This year, at the Canadian National Exhibition in Toronto – colloquially known as the CNE – there was a clear winner in the food challenge: the cronut burger. This heavyweight, coming in at an estimated 7,000 calories, was featured by local, national and international media, all claiming that trying one was a reason to go to the CNE. During the CNE’s opening days, hundreds of people spent $10 each to take in the combination of hamburger meat and maple-bacon jam topped with the latest pastry craze, the cronut, a hybrid cross between a croissant and a donut. By the end of the first weekend, there was little doubt that 2013 was going to be the year of the cronut burger. On Tuesday, Aug. 20, that all changed. Reports of people becoming ill from having eaten at the CNE began to trickle in to local media outlets and Toronto Public Health. The symptoms were consistent, including severe gastrointestinal pain, vomiting, diarrhea and dehydration. By that evening, there were more than a dozen reports, with a handful of hospitalizations, and more were expected. In all, 150 individuals were afflicted. Unlike other outbreaks, however, this one had a common denominator: the afflicted people had all eaten the cronut burger. For food-safety experts, there were really only two etiological contenders. One was the ever-present norovirus; the other was the toxin-producing Staphylococcus aureus. Both had been documented in literature over the past two decades and had the unfortunate ability to cause outbreaks in areas of mass gatherings such as an outdoor fair.  Moreover, they both were known to appear out of nowhere, leading to mass confusion among patrons, significant media attention and the resultant crisis communication from the company in the spotlight. In this case, the company, EPIC Burgers and Waffles, released public statements over the following days explaining the situation and their continued efforts to maintain food safety in conjunction with public-health authorities. By the following Friday, the culprit was identified. It was indeed Staphylococcus aureus, and, based on the investigations, the only uncooked condiment, the maple-bacon jam, was identified as the presumable source. While the team and staff at EPIC Burgers and Waffles felt relieved that they were not the reason for the outbreak, the lasting legacy for the cronut burger may be one of illness, not enjoyment. This case may appear to be unique, but, in reality, it is simply just another addition to the long list of foodborne outbreaks associated with outdoor gatherings such as festivals, fairs and group picnics. In the U.S., the Foodborne Outbreak Online Database has an entire subsection devoted to infections occurring at a fair, festival or other temporary of mobile service. Since 1998, there have been more than 125 such outbreaks, and an analysis of the data reveals some rather unpleasant trends. The food vehicles are fairly diverse, and no one item can be considered to be at a higher risk than others; all foods are at risk of some type of contamination and subsequent infection. The route of contamination can be equally varied from an ingredient, such as the maple-bacon jam in the cronut burger, to the use of imported foods such as produce and fruits, to improper food handling leading to contamination either by the hands or some other environmental fomite. Perhaps worst of all is the potential for high numbers of infected individuals. While most outbreaks pale in comparison to the more than 600 people infected by the recent Cyclospora outbreak – although in an outbreak of Salmonella enterica at the Taste of Chicago festival in 2007 left 802 ill – the clustering effect of these events can lead to an even greater fear. One of the worst offenders is Staphylococcus aureus. While the bacterium only comprises about 10 of the 129 reported incidents since 1998, the number of those infected can be high, with as many as 125 infected in 2000. Moreover, due to the rapid onset of symptoms and the potential for serious consequences as a result of dehydration, there is the potential for a crisis mindset that could lead to significant public concern. At the CNE, the panic never rose to a significant level, yet the outcry from patrons in both regular and social media suggested that the situation could have worsened if the number of cronut burger casualties significantly increased. There is little doubt that maintaining food safety in an outdoor environment can be a challenge. Cramped conditions, climactic changes and a constant line of customers leave very little room for cleanliness. Making the situation worse is the use of casual staff to cook and serve the fare. Yet, even with the most hygienic conditions, there can still be problems associated with improper cooking and chilling. Also, as in the case of the cronut burger, other ingredients contaminated at some other stage of the food continuum. To ensure the highest level of safety, training and surveillance are considered to be the best solutions. At the CNE, upwards of 1,600 individuals go through training offered by Toronto Public Health in order to ensure that those who serve are also helping to protect. In addition to training, the food premises are inspected regularly over the course of the event to ensure that the conditions on Day 1 are the same as on Day 16. Cooking and chilling are continually monitored, and most outlets have a home base where they have proper kitchens to prepare and store their products. As for condiments and other items that are left in the open for public use, they are usually designed to prevent contamination from high traffic and are routinely checked and cleaned before being refilled. There is one more requirement for food safety that continues to be relatively ignored, although, in the case of the CNE, may have saved 150 people from grief. Education of the science behind food and food safety is a must for any food entrepreneur who wants to keep his patrons happy. At the CNE, even with training and surveillance in place, the cronut burger incident would have still happened as the jam was probably contaminated at another site. If education of the science had been implemented, the staff at EPIC Burgers and Waffles would have known that a jar of jam containing meat and sugar could potentially contain bacteria and bacterial toxins. To mitigate this risk, simply bringing the jam up to 48 degrees Celsius (118.4 degrees Fahrenheit) would have inactivated the toxin production and left the jam in its proper state (Editor’s note: This temperature does not kill the bacteria and cannot guarantee the safety of the food. Killing the bacteria requires a temperature of approximately 158 degrees F). By bringing it up to 71 degrees C (158 degrees F), the condiment would have been completely safe.  While the integrity of the jam might be somewhat compromised, to the customer there would be little to detract from its aesthetic value. Even if there had been some noticeable aesthetic loss, the likelihood is that there would have been little economic loss in comparison to the losses as a result of closure. There can be little doubt that training, surveillance and education of the science behind food safety are needed to improve food safety in all areas of the food continuum. When the meadow or the parking lot becomes the kitchen, these needs are even greater. In this environment, food cannot be considered intrinsically safe, and, as a result, those who take on the task of preparing and serving must ensure that their priorities are not only gastronomical. As the most recent event at the CNE has shown, there is much to be gained from simply adhering to scientific principles and so much to be lost from not following them, whether through ignorance or omission.

  • DevourCatering

    I can’t imagine a hamburger on a doughnut tasting good let alone maple, bacon jam…eaww, food poisoning aside

  • Corey

    2 things:
    1. There’s no such thing as Salmonella aureus. I think you mean Staph aureus.
    2. Contrary to your article, Staph aureus toxin is heat stable, meaning it would not have been killed by re-heating the bacon jam bottles to 48C or even 71C. Staph aureus toxin is heat-resistant to temperatures over 100C so once its been formed, it’s pretty much there until consumed.

  • Brandi

    Great article. More often than not, we see a lot of this at our fairs and carnivals. Mix a large number of people-many children-with food that isn’t necessarily prepared or served properly and in the cases of fairs, lots of animals. . .a recipe for disaster!

  • Bob Hendershot

    Is Salmonella aureus correct? Should it be Staphylococcus aureus? Good articles always. I love your newsletter! Thank you.

  • Ben

    Might want to look at the literature on heat stable Staph toxins (and a bunch of historical incidents of staph toxin in heated foods including a large 1989 outbreak linked to a thermally-processed canned mushroom product). Can you share the data that your suggestion of “To mitigate this risk, simply bringing the jam up to 48 degrees Celsius
    (118.4 degrees Fahrenheit) would have inactivated the toxin and left the
    jam in its proper state. By bringing it up to 71 degrees C (158 degrees
    F), the condiment would have been completely safe.” is based on?

    See these references for data related to heat stability of the toxin:

    Bennett, R. W., T. Sullivan, K. Catherwood, L. J. Lukey, and N. Abhayaratna. 1993. Behavior and serological identification of staphylococcal enterotoxin in thermally processed mushrooms, p. 193–207. In S. T. Chang, J. A. Buswell, and S. W. Chiu (ed.), Mushroom biology and mushroomproducts. The Chinese University Press, Hong Kong, China.

    Bennett, R. W. 1992. The biomolecular temperament of staphylococcal enterotoxin in thermally processed foods. J. Assoc. Off. Agric. Chem.

    Evenson, M. L., W. M. Hinds, R. S. Bernstein, and M. S. Bergdoll. 1988. Estimation of human dose of staphylococcal enterotoxin A from a large outbreak of staphylococcal food poisoning involving chocolate milk. Int. J. Food Microbiol. 7:311–316.

    Hardt-English, P., G. York, R. Stier, and P. Cocotas. 1990. Staphylococcal food poisoning outbreaks caused by canned mushrooms from China. Food Technol. 44: 76–77.

    Tatini, S. R. 1976. Thermal stability of enterotoxins in food. J. Milk Food Technol. 39:432–438

  • David K. Park

    I believe that, in this article about cronut burger food poisoning, Mr. Tetro draws an incorrect conclusion and offers misinformation about how to prevent, or at least mitigate, the human health risk of Staphyloccus aureus and its associated preformed enterotoxins in foods, particularly maple-bacon jam. He has unfortunately mislead Food Safety News readers.
    He stated in the article…”If education of the science had been implemented, the staff at EPIC Burgers and Waffles would have known that a jar of jam containing meat and sugar could potentially contain bacteria and bacterial toxins. To mitigate this risk, simply bringing the jam up to 48 degrees Celsius (118.4 degrees Fahrenheit) would have inactivated the toxin and left the jam in its proper state. By bringing it up to 71 degrees C (158 degrees F), the condiment would have been completely safe.” Ironically, I question the science he used behind his information provided.

    He implied that by bringing the jam up to 118.4 degrees F would have inactivated viable Staphyloccus vegetative cells and inactivated bacterial toxins and “left the jam in its proper state.” This is an incorrect statement and leaves the impression to readers that a mild heat treatment is quite sufficient to eliminate the public health risk. What could have been properly stated is “118.4 degrees F is the maximum growth temperature for viable vegetative cells of Staphylococcus aureus present in low-acid foods.” It is, however, important to note that maximum growth temperature is not an equivalent temperature required to thermally inactivate the same organism (and / or its preformed enterotoxins) if already present in low-acid foods, inclusive to cronut burger maple-bacon jam.

    In fact, there is a prolific amount of scientific evidence that both the vegetative cells and their preformed enterotoxins can survive much higher thermal inactivation levels than those quoted in this article. With respect to S. aureus preformed enterotoxins, even sterilization time / temperature levels applied to canned shelf-stable foods is not a reliable means to inactivate preformed Staphylococcal enterotoxins, if present in the food.

    Several viable cell and enterotoxin thermal resistance sources are provided below:

    “The bacteria can be killed through heat treatment of the food, but the enterotoxins are very heat resistant. Although the bacteria are eliminated, the toxins will remain and can cause SFP.”

    Le Loir Y, Baron F, Gautier M. Staphylococcus aureus and food poisoning. Genet Mol Res.2003;2:63–76. [PubMed]

    “For a non-sporing mesophilic bacterium, S. aureus has a relatively high heat resistance
    (Stewart 2003). The observed average decimal reduction value (D-value, the value at which
    the initial concentration of bacterial cells would be reduced by 1 log10 unit) was 4.8–6.6 min
    at 60°C when heated in broth (Kennedy et al. 2005). The bacteria has a higher heat
    resistance when it is encapsulated in oil, with a D-value at 60°C of 20.5 min for S. aureus in
    fish and oil (Gaze 1985). An extremely heat resistant strain of S. aureus (D-value at 60°C of
    >15 min in broth) has been recovered from a foodborne outbreak in India (Nema et al.

    Stewart CM (2003) Staphylococcus aureus and staphylococcal enterotoxins. Ch 12 In:
    Hocking AD (ed) Foodborne microorganisms of public health significance. 6th ed, Australian
    Institute of Food Science and Technology (NSW Branch), Sydney, p. 359–379

    Kennedy J, Blair IS, McDowell DA, Bolton DJ (2005) An investigation of the thermal
    inactivation of Staphylococcus aureus and the potential for increased thermotolerance as a
    result of chilled storage. Journal of Applied Bacteriology 99:1229–1235

    Gaze JE (1985) The effect of oil on the heat resistance of Staphylococcus aureus. Food
    Microbiology 2:277–283

    Nema V, Agrawal R, Kamboj DV, Goel AK, Singh L (2007) Isolation and characterization of
    heat resistant entertoxigenic Staphylococcus aureus from a food poisoning outbreak in
    Indian subcontinent. International Journal of Food Microbiology 117:29–35

    Main reference source for above 4 cited publications:
    With regard to Staphylococcus enterotoxins:

    “Toxins are extremely resistant to heat. For example the D time of enterotoxin B at 149 degrees
    C is 100 min at an aw of 0.99, and 225 min at an aw of 0.90.”
    The most important messages that needed to be conveyed from the cronut burger outbreak are that the vegetative cell transmission to food, resulting in food infection and intoxication, can be principally prevented by use proper hygiene, maintaining proper food temperature, application of other potential preventive controls ( e.g. pH) when appropriate to prevent viable cell growth and preformed toxin production in high risk burger components. Once large numbers of viable cells and preformed Staph enterotoxin were, themselves, components within the maple-bacon jam, there were no other effective means to mitigate the food poisoning risk to the CNE-goers.
    It is also necessary to carefully edit article content, including the unintentional reference to improper genus / species association (i.e. “Salmonella aureus”) in the article.