The public health importance of Listeria monocytogenes as a gastro-intestinal pathogen arises not from the number of reported cases, which is relatively low (10-20 cases annually in Scotland) compared with many other pathogens, but rather due to the severity of infection, high mortality, and the fact that it is foodborne. Infection with Listeria monocytogenes causes influenza like illness, septicaemia or a meningo-encephalitis. Pregnant women, newborn infants, the elderly and immunocompromised are most at risk.
Due to the long incubation period for Listeria monocytogenes (up to 90 days) it is difficult to determine the key sources of infection from traditional epidemiological methods. However, there have been outbreaks in hospitals that have been attributed to sandwiches. Also, sampling of foodstuffs undertaken by local authorities have shown listeria to be present in smoked salmon, cheeses and cooked sliced meats.
Our work is aimed at reducing the risks of Listeria monocytogenes in the production, storage and handling of chilled ready to eat foods which are most commonly associated with human illness. A key priority is to identify effective measures for controlling the organism in the production of ready to eat foods and developing tools to assist food businesses and high-risk food sectors.
We have produced an online tool to help smoked fish producers manage the risk of contamination of their product by Listeria monocytogenes, which is often found in the production areas of manufacturers of smoked fish. This initiative aims to help producers of these foods to follow best practice so they can reduce the risk of contamination of their products.
It is also a priority for us to ensure information about risk and avoidance is communicated effectively so listeriosis can be prevented among high-risk groups. We have been working with FSA to provide guidance for staff with responsibility for providing food in hospitals, nursing homes, etc. to allow them to identify and manage the critical control points specific to controlling Listeria in the food supply chain, with the ultimate aim of reducing the risk of vulnerable groups contracting listeriosis in these settings.