As we say goodbye to the warmth of the fall and hello to winter, our thoughts turn to the season known as the holidays. To mark this special time, we will undoubtedly hear of and be invited to a number of work parties, family gatherings, and social soirees. But while these moments may lead to our hearts being comforted, for many this season, another sensation may occur: gastrointestinal upset.
Foodborne illness is a year-round problem but the holiday season marks an increase in the risk of acquiring an unfriendly microbe intent on having a different type of celebration. The names are common including the egregious E. coli O157:H7, the nefarious norovirus, the loathsome Listeria and the sinister Salmonella. Each one can take away our jubilant joy leaving us with gastric grievances not even the Grinch would take pleasure from witnessing.
Though these microbial menaces are common, the most prevalent cause of bacterial gastrointestinal distress is none other than the calamitous Campylobacter jejuni. This corkscrew-shaped microbe infects more than 100,000 Canadians each year leaving them with a series of symptoms including diarrhea, abdominal pain, fever, nausea and at times, vomiting. Though the numbers have been declining over the years, particularly due to improved food safety, the risks are not only present when going out to eat but also at home.
C. jejuni was relatively unknown until the early 1980s when humans began to show symptoms similar to animals. Upon identification of the microbe as a cause of gastroenteritis, researchers began to question just how this bacterium managed to find its way from the farm onto your fork. The findings suggested the root of the problem was the farm itself; bacteria made their way into animals and then survived processing such that it posed a risk to the consumer.
By 1984, this hypothesis was proven through an analysis of C. jejuni spread in large kitchens. When the animals -- in this case chickens -- were handled, the environments inevitably became contaminated. The skin, the meat and the giblets were all contaminated and without proper hygiene, the microbe could spread across the entire kitchen area. The only places not affected were those kept dry. At the time, researchers believed the key to prevention was to ensure wet environments were treated with disinfection and dried while hands needed to be washed regularly.
As the years went on, the wet factor became critically importance in understanding how the bacterium lived and spread. The most critical component was blood; without it there was no chance for growth. This suggested the bacterium somehow found a way to use blood and other bodily fluids to its advantage. The question of course, was how.
The answer came nearly 20 years later when a novel method for growing the microbe was revealed. Instead of blood, the medium consisted of the juices of the chicken. When the bacteria were introduced, they thrived. How this was possible could not be determined but in terms of foodborne illness, the results revealed something quite troubling. Due to the high level of growth in the juices, one single drop could potentially lead to an outbreak. Yet how chicken juice could allow for such great contamination remained a mystery.
By 2007, the means of spread was discovered. Inside the chicken, on its skin and on other surfaces, C. jejuni was forming colonies known as biofilms. These microscopic civilizations can contain billions of bacteria all huddled around one another. With the flow of chicken juices, thousands from the top layers would be extracted from the group leading to contamination of whatever surface came next. Without proper disinfection and hand hygiene, infections are not just possible, but likely.
Though the biofilm answer helped to impress the need for food safety measures, the question relating to how exactly these biofilms formed remained unknown until this past week. A group of British researchers uncovered the link between the chicken juice and C. jejuni biofilm formation. Based on their observations, the formation of biofilms was dependent on the juices. What was truly surprising was the mechanism allowing for this to occur.
The study was based on a tenet of biofilm formation requiring one or many microbes to anchor onto a surface before the colony can grow. The authors found C. jejuni had a difficult time with this step. When chicken juice was added to make up 5 per cent of the medium, the number of stable attachments increased significantly. When 100 per cent was used -- mimicking the kitchen environment -- the numbers skyrocketed.
The next step was to determine if the juices were needed for growth. The results showed some dependence but even as little as 10 per cent juice was enough to allow the bacteria to thrive. This meant C. jejuni could grow even if the juice was removed and replaced with something as simple as water. In the context of a kitchen, this could be accomplished with a damp cloth wiping down a juice-covered surface. Although visually there is no sign of fluid, at the microscopic level, the environment is still unsafe.
Finding the mechanism behind biofilm formation is a significant step forward in the study of Campylobacter jejuni as it may allow for the development of better disinfectants and other hygiene products. But the results also enforce the need for compliance to good food handling and safety practices. Regardless of the setting, industry or the home, the practices to stay healthy are well known and readily available. By following these simple steps, you can be sure to keep the people around you safe and keep the Holidays a time for joy, not pain.
For more information on how you can prevent foodborne illness head to Health Canada's Safe Food Handling Tips.