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Comment by davycro | Hacker News Reader

I thought all sushi had to be flash frozen to kill parasites. Is this a myth?

You will still eat the worms, not that it is necessarily a bad thing. When I go fish in the south of Norway I see these worms in maybe 1 out of 10 fish I catch. I personally don't eat them but I don't think it's unhealthy as long as they are dead.

Considering health and seafood, I'd be much more worried about is eating Norwegian farmed salmon, that stuff is poison [1]. The amount of toxins has not go down since this article was warning Norwegians.

I never touch it myself and the wild fish you catch close to the mares are monsters compared to the fish that does not consume leftovers from feeding the salmon.

[1] https://translate.google.com/translate?sl=no&tl=en&u=https%3... (Google translate)

I read something recently about AquaStorm, which aims to move fish farms out of the fjords and into deeper sea water, with the purported benefits of avoiding sea lice and disease. Do you have an insider opinion on this?

I'm not an insider, just a Norwegian that consumes seafood :)

But that might help if they reduce the drugs they put in the feed. However I think what needs to happen is that they stop poisoning public waters and move everything to highly controlled on-shore facilities.

I would still be worried about heavy metals etc as the feed contains left-overs from other fish like bones (high in toxins) and fatty tissues that humans don't want to eat.

They take the "role" of the apex predator except for us and it's typical that the higher you are in the food chain the more toxins build up.

As far as I know, most ( or at least All current export I know of ) Farmed Salmon are Deep Sea type Farmed Salmon. The idea is instead of having the possibility of them going to fresh water to spawn, they are kept at specific region of deep sea and greatly reduce the chances of getting parasites.

So I am not entirely sure what the article is suggesting. May be for Salmon that is not intend to be served as sushi? Because Freshwater Salmon doesn't fit that bill.

At least for the US, they requires some type of process but it is messier than perhaps it should be. For one the responsibility for freezing the fish can be shifted between the restaurant serving and the vendor, and might not be effective. This is because time tables for acceptable methods of freezing fish vary in length depending on the temperature they are stored at. Some of the higher temperatures takes a couple weeks, and for example a restaurant might be buying fresh fish and not storing them in a freezer long enough.

> Is this a myth?

No. Fish for sushi is recommended to be flash frozen or frozen for X number of days to kill the parasites. FDA recommendations for freezing fish to kill parasites.

"Freezing and storing at an ambient temperature of -4°F (-20°C) or below for 7 days (total time), or freezing at an ambient temperature of -31°F (-35°C) or below until solid and storing at an ambient temperature of -31°F (-35°C) or below for 15 hours, or freezing at an ambient temperature of -31°F (-35°C) or below until solid and storing at an ambient temperature of -4°F (-20°C) or below for 24 hours are sufficient to kill parasites. Note that these conditions may not be suitable for freezing particularly large fish (e.g., thicker than 6 inches). "

https://www.fda.gov/media/80777/download

You could freeze fish in your freezer since most freezers can do -4°F or lower, but it will just take longer to kill the parasites.

People also catch fish, check for parasites visually and then prepare it sushi/sashimi style and eat it. Even here, you'll generally be okay but the odds of getting sick increases.

Also, the article is from eurekaalrt and the headline is clickbait nonsense.

Even if "sushi parasite" increased 283 fold, what's the increase in sushi consumption? It went from pretty much 0 40 years ago to being almost ubiquitous today.

I'm pretty sure "sushi grade" fish is fish that has been frozen properly, and restaurants have to follow FDA guidelines on raw foods like this. It's not just a good idea, it's the law (in the US).

Honestly, my wife and I often forego the freeze step when we make sushi at home. Yes, it's an increased risk, but it's a risk we both accept, and since we typically buy fillets, it's quite possible that it has already been frozen properly but the store isn't comfortable making guarantees.

Last I saw, that was the case in the U.S. but not Japan. Sometimes there were still U.S. cases from people making sushi at home. I'm no expert though.

I believe this the case for fish in general

https://www.youtube.com/watch?v=m0Dq6_HHfUA <3 Brad

Per the article, “increased 283-fold” means a specific variety of worm is now more common in the fish. It doesn’t mean parasites have become more common in people. It’s consistent with these results for sushi freezing to still kill the worms.

Not all fish is required to be frozen to kill the parasites actually. there are classes of fish that are considered not significantly dangerous to warrant that procedure. I looked up the fda guidelines on it a while ago.

I heard flash freezing can make the sushi taste better too. Does anyone know if this true?

The effect of freezing on taste is certainly subjective, but it is not seen to be detrimental to the taste or texture. In fact, several renowned masters are in record as preferring there fish to be raw at purchase and then they freeze them themselves using low temperature deep freezers for set periods of time. I do find the effects of freezing to enhance the preparations, but then I tend to agree with the Japanese philosophy that sushi is about the rice, and the fish is just a condiment.

Well yeah, sushi is the rice itself, while sashimi is the raw fish itself. If you have a mixture of both, it's still called it sushi. You can also have sushi with vegetables or fruits and no fish or meat. Your sushi can come with or without seaweed.

Korea has a similar dish called kimbap, which literally translates to "seaweed rice", so having something other than a roll wouldn't be kimbap anymore. Also, Korean kimbap uses a different recipe for the rice (usually sesame oil and salt), so it can't even be considered a special case of sushi (rice with vinegar and sugar).

I feel far too many people don't understand what sushi is, even if the consider it one of their favorite foods.

It's a recommendation by the FDA in the US, not an enforced regulation.

Except Tuna, because Tuna is known to be exceptionally clean fish. Salmon definitely needs to be frozen.

Exception is for very deepwater fish like yellowfin tuna and skipjack.

same

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