Finding out more about what conditions can reduce Listeria, better practical advice and updated recommendations are all important goals. The aim is to help us as consumers to continue to enjoy the great diversity of local cheeses in the confidence that they are safe to eat.
An important current issue
In the autumn of 2007, 21 people were hit by an outbreak of the illness Listeriosis. Five of them died. The report from the Norwegian Food Safety Authority showed that the source of infection was soft cheese produced at a farm dairy in Nord-Trøndelag. Closer investigation showed that Listeria was present both in the products and in the production area. The effects were so serious that the cheese maker chose to close down production for good. The incident was tragic for those who contracted the illness, it was tragic for the producer and it affected the entire industry.
As this example shows, infection from Listeria is a current problem and soft cheeses are products that carry a risk. There is a need to find out more about where the areas of greatest risk are among smaller cheesemakers, so as to prevent Listeria and find effective ways of monitoring production through sample taking and analysis.
Gathering data, interviews and visiting producers will increase our understanding
As a first stage, data will be collected from small-scale Norwegian cheese producers about products, production methods and traditions, environment and equipment. This is necessary because these factors can be very different from what we know from the major cheese producers, and also because there are wide variations between the different smaller producers. Following this review, interviews and visits will be carried out with selected producers to take a closer look at premises, equipment and the production process. This, together with similar information from France, will help to give us a better understanding of the process by which cheese becomes infected with Listeria and what factors can influence this.
It is a further aim of the project to look more closely at the Listeria strains that are showing up more frequently in cheese production. This will include investigation into how Listeria can survive on different materials and at different temperatures and whether varying growth conditions affect the bacteria's ability to cause illness. The interaction between Listeria and naturally occurring bacterial cultures and types of mould will also be studied more closely.