You can see and smell if a fish is good, but determining its keeping quality requires more precise methods. At Aqua Nor, Fiskeriforskning demonstrates a freshness gauge that gives the answer at once. To determine how fresh the fish is - and provided it has been properly stored - fish fillet producers work out the time since the fish was caught.

Different species of fish have different keeping qualities. For example, fresh salmon can be stored several days longer than fresh cod under the same storage conditions.

To more precisely determine how long the fish remains good, a bacteria counter is commonly used. But today’s methods take time to produce results and often only one indicator of freshness is measured, such as texture, odour or colour.

Gauge freshness as quick as one-two-three

In recent years, researchers at Fiskeriforskning have developed a new measuring instrument that takes into account several factors. By using light at different wavelengths, it can quickly determine how fresh the fish is.

“This method is very reliable and can be used by seafood counters as well as in the industry to ensure that the product delivered is of good quality”, explains senior researcher Heidi Nilsen.

The freshness gauge is so fresh that it is not yet on the market, but it is being demonstrated at the Aqua Nor aquaculture exhibition in Trondheim, Norway, this week (Aug 2007).

Read also: Is your fish sushi fresh?

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