Is the fish used in sushi frozen or not?

I have just discovered that almost all the fish consumed raw in Europe has been previously frozen, because European regulations require it, to control parasites.

But there is quite a controversy on the subject among specialists. Some say that, from a health point of view, it is essential to freeze fish. They also say that freezing does not change the taste or texture of the fish when it is done properly. Others claim that eating fish that has not been frozen poses little risk if it is well prepared, and that freezing significantly alters the taste and texture of the fish.

I would like to know what the current situation is in Japan, in cheap sushi chains on the one hand, and in good restaurants on the other.

> In your opinion, in sushi restaurants in Japan, what is the average percentage of fish that has been frozen before? Let's limit ourselves to the case of nigirizushi.

> What is the most important factor in determining whether the fish has been frozen or not? The species? The type of restaurant? The region of Japan? The time of the year?

>For those living in Japan: have you ever noticed a difference in taste or texture between raw fish that has been previously frozen, and not frozen?

The following topic has already addressed the issue last year, but the answers are quite contradictory in terms of what is common or not: https://www.japan-guide.com/forum/quereadisplay.html?0+156739

raw fishes have been eaten in Japan, before we invent freezing machines.
thus, for eating raw fishes, "freezing" is not essential.
in many cheap restaurants, frozen fishes are served, because those are CHEAPER than fresh raw fishes.
if you have a sensitive tongue, those two can be distinguished.
in another word, for persons can't distinguish those two, those may be realizes as the same.

My opinion... Yes, all chains will use once frozen fish since it is safer and protects their brand. A chain will use only once frozen, throughout the year, and for all species. I cannot tell the difference in taste. But texture may be a bit softer than unfrozen that I catch or that which is given to me by a fisherman.

That people ate unfrozen fish prior to the technology to freeze, or that some people eat what they catch unfrozen does not sway me. They got anisakiasis (a small worm that attaches itself in your stomach). I had one too - that came from a small restaurant that served self-caught fish that they did not freeze. I had mine removed thru endoscopy.

Tuna is almost always frozen in my experience. I feel sorry for the fish, but freshly killed fish tastes so much better, though I prefer not to see it all happen.

Remember that the best way of keeping some fish fresh is to freeze it immediately when you catch it.

Deep-sea fishing boats are often away from port for some time. Big tuna, for instance, live a long way out into the ocean, and the boats that catch them are equipped with state of the art very cold fast-freezing equipment. If this fish was kept unfrozen, it would not be in very good condition by the time it reached your plate.

Fish caught on day boats in inshore waters (or grown in fish farms), can be put on ice and eaten without the need to freeze them because they can be back on shore and eaten before they have gone bad.

Some fish (e.g. mackerel) go bad more quickly than others, and so they are most typically preserved by e.g. vinegaring. Remember that sushi was historically all about preserving the fish. Hence the use of vinegar in the rice, and of wasabi and shiso - all of these things act as antibacterial agents to some extent.

Also add in the fact that some sushi chefs will age fish on purpose, to develop different textures and amino acids.

"Freshness" isn't such a simple concept, or necessarily to be associated with not using a freezing process, or necessarily always the thing which gives the best taste.

one of the most expensive tuna,マグロ will never be frozen.

also, you can find non-frozen tuna very easily in supermarkets.

I think you're saying "maguro", ken, which I think is what we would call in English "bluefin tuna". Apologies for not being able to read Japanese.

Quite possibly most of the Bluefin tuna caught in Japanese inshore waters (such as in the straights between Hokkaido and Honshu, which, I believe is very highly prized), will not need to be frozen, as you say.

However, most of the bluefin tuna in the world lives in and around the South Pacific, and the boats that go that far to catch that Bluefin will be out at sea for many months - so of course they freeze it. Bluefin tuna also lives in the Atlantic, and around Europe...it's not just Japanese.

the reason to be frozen is that they are caught extremely far away from consumer places. it is impossible to bring them in raw state. there is no other way except for doing that. freezing is un-necessary to eat.
I heard that tuna, harvested in Mediterranean sea is imported by air to Japan in raw state,( not be frozen), because they are good quality. thus, low quality and cheaper tunas are frozen, while expensive raw tuna in sashimi and sushi dishes are non-frozen.

Kiikatsuura is famous for its fresh tuna market and many restaurants in town get theirs from there. One restaurant opposite Kiikatsuura Station called Bodai has this divine toro katsu as their speciality

https://en.visitwakayama.jp/wonderfully-wakayama/melt-in-the-mouth-tun...

Most sushi chef claims if flash frozen (using liquid Nitrogen) and thawed properly, the tuna can be as good as fresh. Flash freezing is done immediately after caught, on the boat. Here in Hawaii, most tuna are sold flash frozen at the auction market. But you can also buy never-frozen, mostly from smaller boats like chartered fishing boats. There is one eatery that advertises never to use frozen tuna and I have eaten their poke a few times. I don't know what their definition of "fresh" is, but, personally speaking, I prefer the flash frozen variety from a reputable sushi bar. The issue with fresh-never-frozen is you don't know how many hours or days the tuna has been dead and kept on ice. In the old days before refrigeration, sushi eateries in Japan served only locally caught fish (except for cooked/smoked/cured fish, of course).