Project Year 2014
Clipfish and shelf life
Clipfish is being studied in various storage condition. The aim is to arrive at the correct recommendation for shelf life.
An ongoing research project is studying the shelf life of clipfish at elevated temperatures. All food producers put a use-by date to show how long the quality is retained. All clipfish is currently being declared with a 12-month use-by date, which is not correct in markets with warm climates and a lack of refrigeration facilities. Red halophilic bacteria are found in the sea salt that is used in the production of the fish and high temperatures make these bacteria grow faster. When the number of bacteria reaches 10 million per gram, the clipfish takes on a visible pink discolouration. These bacteria occur naturally and are harmless, but the high temperature gives the fish an undesirable red colour. Scientists have now found out why.
«These bacteria do not grow below eight degrees. Above eight degrees, they start to grow and we have studied the rates of growth at various temperatures and
humidity levels. After comprehensive sampling, we can now state that clipfish can be kept at 30 degrees for at least 15 days. Currently, clipfish is being marked with a 12-month shelf life provided a storage temperature of 4 °C. Since there is no reason to suppose that the quality decreases over the course of one year, we will now attempt to produce documentation that clipfish can be kept for two years,» explains Grete Lorentzen, Senior Scientist at food research institute Nofima.
The clipfish being studied now has been under refrigeration since the project started in 2013. Every six months, the fish is photographed with a special camera
that provides extremely high resolution. The scientists are thus able to study any physical changes in the fish over the storage period. A sensory analysis is also performed, in which odour and appearance are assessed, and of course the level of red halophilic bacteria is studied carefully throughout the course of storage.
The result of the project is factual information that will increase knowledge about shelf life. This will primarily benefit the klippfisk industry, but it will also provide useful information for markets and consumers.
The Norwegian Seafood Research Fund