…a well-established sushi restaurant. Why? That fish you’re eating was flash frozen solid at a temperature of -35°F and stored that way in a commercial freezer for at least 15 hours to kill whatever parasites happened to be in it.
Your favorite sushi joint also probably buys their fish from a seafood processor, which inspects the fish before it’s sold. Using a process called “candling,” they shine light through the fillets to look for any abnormalities, including bones. Then they either remove them or discard the fish. Many seafood processors probably get a lot of their product from fish farms, which is less likely to be riddled with worms. Multiple studies have found that fish from hatcheries have far fewer incidents of parasites, while wild-caught fish can have a very high rate of infection.
So what can you do?
Do a little research: Find reputable sushi restaurants and ask them where they get their fish. Is the seafood processor known for quality? Is the fish the restaurant serves farmed or wild-caught? Do they freeze their fish according to FDA regulations? They’ll likely be more than happy to tell you the great lengths they go for quality food. Remember, sushi chefs are trained for years to deliver you delicious fish that’s safe to eat. If they don’t, they go out of business.
Freeze and candle your own fish: If you’re preparing sushi or sashimi at home, you’ll have to be patient. You should buy thinly-sliced “sashimi-grade” fish at a reputable market, candle it, and pop it in the freezer for a whole week since it can only get to about -4°F. At that temp, it takes a lot longer to kill everything off. It was probably already flash frozen, but better safe than sorry.