Is because Diphyllobothriasis, cestode larvaes from freshwater fishes that can be very dangerous for humans; but the fish metazoan parasite that send more sushi lovers to the hospital is marine in fact.

Anisakiasis by roundworm larvae in raw fish or squid normally is not a big problem but is painful, and can lead to serious health issues sometimes. Any competent japanese chef will know how to deal with it. European law obliges to restaurants to frozen all fish destined to be served as sushi just for this.

"European law obliges to restaurants to frozen all fish destined to be served as sushi just for this."

Really ? All fish served as sushi in Europe has been previously frozen ?

I can not speak for all asiatic restaurant owners in London, Berlin or Paris, but most chefs specialized in serving raw fishes do not joke about this and avoid the problem using special ultra-freezers. This reduces the safety-time to several hours (It is known that Anisakis larvae can survive for about a week in a domestic freezer) and helps to keep the quality of the sashimi. Thus, when you hear 'fresh', you probably should decode this as 'ultra-frozen in fresh' as something totally natural.

The cut of sashimi in translucent fine lames is probably a way to detect and clean the fish of any visible parasites before to serve it. Exposing the beauty of the fish muscle in intrincated designs you are also showing the client that your product is of optimum quality and totally clean.

Here's the UK implementation: https://www.food.gov.uk/business-industry/fish-shellfish/fre...

I'm not sure if this archived page is still accurate: http://webarchive.nationalarchives.gov.uk/20150624093026/htt...

Many types of fish used for sushi in Japan have been frozen at some point because commercial trawlers spend weeks if not months at sea, and the catch has to be frozen or left to spoil.

It's the same in the US. If a restaurant is claiming the fish is not frozen, they are breaking the law and eating the fish is significantly more dangerous.

I am not sure about Europe, but that's the law in the US too (there are a few exceptions).

That's why this was such an interesting story, battling prejudice and ancient folk wisdom is no simple task. Here's a typical Norwegian salmon farm http://i0.wp.com/blogg.seafood.no/wp-content/uploads/2013/02.... This is a sea-water farm and the fish is vaccinated early on and live a healthy antibiotics free life until they end up on your sushi (sour-tasting rice).

fish farms had just gone commercial in the 70's but hadn't grown that much at the time. the excess of high quality fish was wild salmon.

in the 70's in norway (and in alaska, can't speak about anywhere else) commercial fishing was in it's prime.

you can read more about the history of norwegian aquaculture here. http://www.svt.ntnu.no/iso/anders.skonhoft/Marine%20Policy%2...

Only eat raw salmon that has been flash frozen. This will kill the pesky parasites, according to the chef at a sushi restaurant I used to frequent.

My favorite sushi chef lightly smokes his salmon.

No, according to that logic, you shouldn't eat raw beef, pork and chicken. Which is a highly advisable precaution - not following it will result in a high chance of critters like Taenia Saginata or Trichinella spiralis making a home inside you.

Trichinella is actually vanishingly rare in US commercial pork today. Most cases these days come from boar and other wild game.

http://www.cdc.gov/parasites/trichinellosis/epi.html