No Anisakis in farmed rainbow trout

Foto: Tom Haga/Norges Sjømatråd

No Anisakis was found in farmed rainbow trout intended for human consumption, shows a new report from NIFES.

NIFES has analysed a total of 1,038 rainbow trout farmed in sea cages at 15 different fish farming facilities along the coast, from Northern Norway to Western Norway. Anisakis (Anisakis simplex) was not found in any of the fish intended for human consumption.

‘We consider it highly unlikely that we will find Anisakis in food quality farmed rainbow trout,’ says Irja Sunde Roiha, scientist at NIFES.

Findings in loser fish

Anisakis was found in five loser fish from three different fish farming facilities. Loser fish (runts) are fish that are not selected for human consumption. They differ from normal trout in terms of size and appearance and are discarded early in the harvesting process.

There are clear EU and EEA guidelines on how to handle fish that is to be eaten raw in order to prevent people from consuming Anisakis that can make them ill. All wild fish that is to be eaten raw must be frozen first. When the fish is frozen to a core temperature of minus 20 degrees Celsius for 24 hours or minus 35 degrees Celsius for 15 hours, any Anisakis will die. Normal preparation methods for wild fish, such as frying and boiling, will also kill Anisakis.

No freezing requirement for salmon

For a long time, Norway’s practice has been to exempt Atlantic salmon (Salmo salar) from the freezing requirement, since it has been documented that the risk of this fish containing parasites is negligible. The Norwegian Food Safety Authority is now making efforts to formalise this exemption in the regulations.

NIFES’s analysis is the biggest of its kind on parasites in farmed trout, both nationally and internationally. The project was funded by the Norwegian Seafood Research Fund (FHF).