Many seafood connoisseurs will tell you that fresh fish is without a doubt the best kind to use, with frozen coming in a distant second. According to a new study from Norwegian research group SINTEF, however, frozen fish can be just as good as fresh, if not better – as long as the correct steps are followed.
The study, which was conducted in collaboration with the Norwegian Institute of Nutrition and Seafood Research (NIFES) and the Icelandic research institute Matís, compared fresh and frozen cod.
To start with, it was determined that the fish must be frozen as soon as it's hauled aboard the fishing boat, before rigor mortis sets in. It must then remain frozen at a stable and low temperature, right up until it's being thawed for resale.
The thawing process itself itself should be done in water, with air bubbles added for best results.
In lab tests, the scientists first tried thawing the fish over a period of 28 hours, starting with a water temperature of 10 ºC (50 ºF) that was gradually lowered to 0.5 ºC (33 ºF). They then tried thawing it at a constant temperature of 10 ºC, over a six-hour period. The quality of the thawed cod was very similar in both cases, to the point that the researchers state the fish shouldn't be thawed for more than 28 hours.
When the thawed and then refrigerated fish was subsequently tested for factors such as bacterial content, texture, colour, airiness and consistency of the flesh, it was found that it remained at "top quality" for up to 10 days.
"I hope that these research results may contribute towards opening people's eyes to frozen fish, which in some cases is better than fresh fish," says SINTEF scientist Guro Møen Tveit. "After all, it often takes many days before fresh fish reaches the sales counters."