Sushi made with raw fish is generally safe to eat, but that safety depends almost entirely on how the fish was handled, stored, and prepared before it reached your plate. At a reputable restaurant following proper food safety practices, the risk is low. But raw fish does carry real hazards that cooked fish doesn’t, including parasites, bacteria, and histamine buildup, so understanding what makes it safe (and what doesn’t) matters.
How Parasites Are Controlled
The biggest biological concern with raw fish is parasites, particularly a roundworm called Anisakis. Japan, where raw fish consumption is highest in the world, reports roughly 20,000 cases of anisakiasis per year. Infection causes intense stomach pain, nausea, and vomiting, typically within hours of eating contaminated fish. Most cases resolve on their own or after the larvae are removed during an endoscopy, but it’s not a pleasant experience.
The primary defense against parasites isn’t freshness. It’s freezing. The FDA recommends that fish intended for raw consumption be frozen at -4°F (-20°C) for at least 7 days, or flash-frozen at -31°F (-35°C) until solid and then held for 15 to 24 hours depending on storage temperature. These temperatures kill parasites reliably. Nearly all fish served raw at sushi restaurants in the U.S. has been frozen to these specifications at some point in the supply chain, even if the menu says “fresh.” This is a feature, not a drawback.
“Sushi Grade” Means Less Than You Think
If you’ve seen fish labeled “sushi grade” at a grocery store or fish market, you might assume that label guarantees safety for raw consumption. It doesn’t. The FDA does not regulate or define the term “sushi grade.” There is no federal standard behind it. Retailers are free to define it however they choose, and definitions vary wildly from one store to the next. In practice, the label often reflects the retailer’s own assessment of freshness relative to their other fish, not adherence to any parasite-killing freezing protocol.
This matters most if you’re preparing sushi at home. Buying fish from a trusted fishmonger who can confirm the product was frozen to FDA parasite-destruction standards is far more meaningful than any “sushi grade” sticker. If you can’t confirm the fish was properly frozen, you’re taking on a risk that restaurants have already managed for you.
Bacterial and Histamine Risks
Parasites aren’t the only concern. Raw fish can harbor bacteria like Salmonella, Listeria, and Vibrio species. Vibrio vulnificus, found in warm coastal waters, is particularly dangerous: roughly half of infections from this bacterium are fatal, with death occurring within about 48 hours of consumption. These infections are rare, but they’re far more common in people with compromised immune systems or liver disease.
Temperature control is the main line of defense against bacterial growth. Raw fish should stay refrigerated until the moment it’s prepared and served. The longer it sits at room temperature, the faster bacteria multiply. At a well-run sushi restaurant, fish is stored on ice or in refrigerated cases and handled quickly. At home, keep raw fish cold until you’re ready to use it and consume it the same day you buy it.
There’s also a lesser-known hazard called scombroid poisoning, which comes from histamine buildup in certain fish. When dark-fleshed species like tuna, mackerel, sardines, and anchovies aren’t kept cold enough after being caught, bacteria in the fish convert an amino acid in the muscle tissue into histamine. Eating fish with high histamine levels triggers symptoms that look a lot like an allergic reaction: facial flushing, rash, headache, palpitations, abdominal cramps, nausea, and sometimes difficulty breathing. Symptoms start within 10 to 90 minutes and usually resolve within a day or so. Cooking doesn’t destroy histamine once it’s formed, so this risk applies to cooked fish too, but proper cold-chain handling prevents it from building up in the first place.
Mercury Levels Vary by Species
Mercury is a concern with any fish consumption, raw or cooked. Cooking doesn’t reduce mercury, so this risk is the same whether you eat sushi or a grilled fillet. What matters is which fish you choose and how often you eat it.
Salmon is one of the lowest-mercury options on a sushi menu, averaging just 0.022 parts per million (ppm). Skipjack tuna, often used in cheaper rolls, averages 0.144 ppm. But bigeye tuna, the rich, deep-red cut served as premium maguro at many sushi bars, averages 0.689 ppm and can reach as high as 1.8 ppm. Yellowfin tuna falls in between at about 0.354 ppm. For context, the FDA’s action level for mercury in fish is 1.0 ppm.
If you eat sushi occasionally, mercury is unlikely to be a concern regardless of species. If you eat it multiple times a week, favoring salmon, shrimp, and lighter tuna varieties over bigeye tuna will keep your exposure well within safe limits.
Who Should Avoid Raw Fish
Certain groups face higher risks from raw seafood. The American College of Obstetricians and Gynecologists advises pregnant women to avoid raw fish and shellfish entirely because of the elevated risk of foodborne illness. Listeria, in particular, can cross the placenta and cause miscarriage, stillbirth, or serious infection in newborns. People with weakened immune systems, liver disease, or diabetes are also more vulnerable to severe outcomes from Vibrio and other bacterial infections. Young children and older adults fall into this higher-risk category as well.
For these groups, cooked sushi rolls, vegetable rolls, or sashimi alternatives made with cooked shrimp or eel are safer choices that still let you enjoy the meal.
Nutritional Benefits of Raw Preparation
One genuine advantage of eating fish raw is nutrient retention. Fish is an excellent source of protein, omega-3 fatty acids, and vitamin D. While research shows that most cooking methods (boiling, grilling, frying) retain vitamin D at levels comparable to raw fish for most species, some nutrient loss does occur depending on temperature and cooking time. Omega-3 fats are sensitive to high heat, so raw preparation preserves them fully. This isn’t a dramatic difference for most people, but it’s a real one.
How to Judge Quality at a Restaurant or Store
Whether you’re sitting at a sushi bar or shopping for fish to prepare at home, a few sensory checks go a long way. Fresh, safe raw fish should have a clean, mild, ocean-like scent. A strong fishy smell is the clearest warning sign that something has gone wrong with storage or handling. The flesh should look vibrant in color, not dull or discolored. When touched, it should feel smooth and slightly firm, bouncing back when pressed gently rather than leaving an indentation. Fish that feels mushy, slimy, or breaks apart easily is past its prime.
At restaurants, general cleanliness and how fish is displayed matter. Fish sitting behind a clean glass case at a cool temperature is a better sign than fish sitting out in open air. High turnover is your friend: a busy sushi restaurant moves through its inventory quickly, which means fresher product on your plate.