What 'Sushi Grade' Fish Actually Means (and What It Doesn't)

Walk into almost any fish market and you’ll see salmon or tuna labeled “sushi grade.” It sounds like an official certification. It’s not. No US government agency defines the term, regulates its use, or verifies what it means when a vendor applies it to their product.

That doesn’t mean raw fish safety is a free-for-all. The FDA does have actual requirements for fish intended for raw consumption. Those requirements just don’t use the words “sushi grade.”

What the FDA Actually Requires

The FDA’s Fish and Fishery Products Hazards and Controls Guidance requires retail food establishments to freeze fish before serving it raw. The specific time-temperature requirements for killing parasites are:

• -4°F (-20°C) for 7 days (the most common approach, achievable by most commercial freezers)
• -31°F (-35°C) until solid, then store at -31°F for 15 hours
• -31°F (-35°C) until solid, then store at -4°F for 24 hours

These temperatures kill parasitic worms and larvae — specifically Anisakis and Diphyllobothrium — that can survive in raw fish flesh.

When a fish counter calls something “sushi grade,” what they should mean (though aren’t required to mean) is that this fish has been frozen per one of these FDA protocols. You have to ask to find out whether it actually was.

The Parasite Problem

Anisakis is a genus of parasitic roundworms that infect the flesh of many ocean fish. Salmon, herring, mackerel, halibut, cod, and anchovies are all commonly infected with Anisakis larvae. The worms enter the fish when the fish eats infected prey in the ocean and migrate into the muscle tissue.

When an infected, unfrozen piece of fish is eaten raw, the live larvae can attempt to penetrate the human gastrointestinal wall. This causes anisakiasis: intense stomach pain, nausea, and vomiting typically within 1 to 12 hours of eating. In some cases the larvae penetrate the gut wall, requiring surgical removal. Even dead larvae can cause an allergic reaction in some people.

Diphyllobothrium is a tapeworm with a complex lifecycle involving fish. Human infection from eating raw fish leads to intestinal tapeworm infection that can persist for years and cause nutritional deficiencies, particularly vitamin B12 depletion.

Both parasites are killed by proper freezing or by cooking to 145°F internal temperature.

What Freezing Doesn’t Fix

This is the part that surprises most people who learn about FDA freezing requirements and think raw fish is therefore safe.

Freezing kills parasites. It does not kill bacteria. Bacterial pathogens in raw fish — Vibrio parahaemolyticus (found naturally in warm ocean waters, common in shellfish), Salmonella, and Listeria monocytogenes — survive freezing temperatures and remain viable after thawing.

Vibrio is particularly relevant for raw oysters and raw fish from warm-water sources. It multiplies very rapidly above 50°F and can cause severe illness within 24 hours of ingestion. Listeria is a concern for raw fish products because of Listeria’s particular danger during pregnancy.

The bacterial risk in raw fish comes down to three things: the initial bacterial load in the fish, the handling and temperature maintenance throughout the cold chain, and how fresh the product is at time of consumption. None of these are indicated by the words “sushi grade.”

Farmed vs Wild

The FDA’s parasite-control requirements apply to most wild-caught ocean fish. But they acknowledge an important exception: fish raised in aquaculture facilities on parasite-free feed have a much lower parasite risk.

Farmed Atlantic salmon, raised on processed pellets in controlled net pens, typically don’t harbor Anisakis because the larvae enter fish through the food chain — specifically through infected prey. Farmed salmon don’t eat wild prey. The FDA’s guidance allows for raw serving of aquaculture-raised fish without the freezing requirement when the establishment can document the parasite-free feed program.

This is why “farm-raised salmon” at sushi restaurants is sometimes served fresh rather than previously frozen, and it’s legitimate from a parasite-risk standpoint. Bacterial risks still apply.

Buying Raw Fish for Home Use

When you buy fish to serve raw — for sashimi, crudo, ceviche (note: the acid in ceviche doesn’t reliably kill parasites), or sushi — the questions to ask are:

1. Has this been frozen per FDA parasite-control guidelines?
2. How fresh is it? When did it come in?
3. What is the turnover here? (High-turnover fish counters at good seafood markets or Japanese grocery stores tend to have fresher product.)

Don’t let the label “sushi grade” answer those questions for you. Ask them explicitly.

For high-risk individuals — pregnant women, elderly adults, immunocompromised people, young children — the safest advice is to avoid raw fish entirely. The combined parasite and bacterial risks in raw seafood are meaningful, and they’re disproportionately dangerous in these groups. The food safety during pregnancy article covers this in more detail, including the specific raw fish risks for pregnant women.

The freezing and thawing guide covers how home freezer temperatures compare to FDA parasite-control temperatures — an important distinction for anyone who thinks freezing fish in their home freezer makes it sushi-safe.