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Bacteria that grow on surfaces can produce a slime that causes a coating we call biofilm. This is created particularly rapidly on surfaces that are constantly damp and not regularly cleaned, such as production equipment where cleaning is difficult.

Biofilm can present a problem with cross contamination during the production of food. Nofima Mat is researching into how the formation of biofilm is affected by environmental conditions and how biofilm can be controlled.

Listeria monocytogenes is a bacterium that can cause serious illness via food and that can attach itself to many types of materials, including steel and plastic polymers. Listeria monocytogenes can also survive in cracks and scratches in materials and in nooks and crannies inside equipment. In general we find Listeria monocytogenes most often in niches that are not sufficiently washed. Localised populations can establish themselves in the premises and survive for years without being eradicated. It has also been observed that these established populations of Listeria monocytogenes can, to a certain extent, fasten themselves to surfaces more easily than sporadic invasions. This tends to indicate that the establishment of these special populations is linked to the ability to create biofilm.

Usually finds of Salmonella and E. coli on surfaces are looked upon as indicators of fresh faecal pollution. Research that Nofima Mat is involved in indicates that these bacteria can create biofilm and that they can survive on surfaces for extended periods. More research is necessary to clarify whether these bacteria can establish themselves in the food industry and the extent to which biofilm plays a role here.

Staphylococci will often be the dominant bacteria on surfaces in the food industry. Most staphylococci, including Staphylococcus aureus, can create biofilm on the materials that are used by the food industry. Research at Nofima Mat has shown that the creation of biofilm is stimulated when the bacteria are stressed, for example with high salt concentrations or at low or high temperatures.


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