Listeria monocytogenes is a bacteria that can be found on foods such as ready-to-eat meals, fish, cold meats, hot dogs, deli meats, pasteurized or unpasteurised milk and soft cheeses such as Brie and Camembert. It can also be present on raw meats, ice cream and raw vegetables, therefore the potential for contamination can be seen to be high when considering the range of popular foods common to the food chain.
However clinical tests show the actual levels of contamination on these foods to be low when compared with pathogenic bacteria such as Salmonella, but the mortality rate from the resultant disease, Listeriosis, approaches 25% of infected cases whereas in Salmonella cases the mortality rate is far closer to 1%.
Listeria is a genus of bacteria that contains ten species, but it is the L. monocytogenes that is the causative agent of Listeriosis. In very simple terms the bacteria invades cells in the hosts body and then by growth contaminates the adjacent human cells.
This can then lead to a number of mild flu-like symptoms, such as nausea, vomiting and diarrhoea which in a healthy body may be defeated by the immune system, but the potential for escalation to more life threatening complications such as sepsis and meningitis, is high in the vulnerable such as the elderly, pregnant women, newborn infants and people with weak immune systems.
The reason why particular training for food handlers as a part of their Food Safety training may be required is that the Listeria monocytogenes pathogenic bacteria can exist and multiply outside of the standard range of temperatures defined by the majority of food handling training as safe.
The Food Safety Certificate Level 2 training as accredited by the Chartered Institute of Environmental Health is recognised as one of the gold standards of UK/EC food training and conforms with all Food Act recommendations as laid down by the UK Food Standards Agency. However this identifies the “Bacterial Danger Zone” to be between the temperatures of 8 – 63 degrees Celsius, whereas L. monocytobenes bacteria are still capable of growing and multiplying at temperatures as low as 4 degrees Celsius.
Food handlers will know that many more subtle foods can be damaged if chilled to below 4 degrees Celsius and so the 8 degree temperature requirement is acknowledged by most as an acceptable compromise level for targets to be set at, yet without further training on the dangers such as L. monocytogenes a significant hazard to health may be allowed to enter the food chain with dangerous effect to the vulnerable members of society.
Based on the fact that 1470 cases of Listeriosis were registered in the EU in 2011 and the popularity of eating away from home continues to grow it is my opinion that the current Basic Food Handling, Food Safety Training should have added to it an additional section on how to minimise the potential contamination of this dangerous pathogen and to increase awareness that even adhering to the 8 degrees Celsius minimum temperature to the Danger Zone, does not completely illuminate all risk.
Hobson Tarrant