To buy fish for sushi at home, go to a supplier who can tell you the fish has been frozen to parasite-destruction standards or is a species that's exempt. Look for firm, bright, clean-smelling flesh, keep it cold from the counter to the plate, and use it quickly. "Sushi-grade" is a useful signal, but in the UK, EU and US it's a marketing term, not a legal grade. What makes raw fish safer is how it has been frozen, stored and handled, not how fresh it is. No raw fish is entirely risk-free, but good buying and handling reduce the risk considerably.
What "sushi-grade" really means
No government agency inspects fish and awards it a "sushi-grade" label. What is regulated is the process. Businesses that sell fish for eating raw are generally required to freeze it to set conditions that kill parasites, unless the species is exempt. So when a shop says "sushi-grade", it means it believes the fish is suitable to eat raw. Whether that's true depends on the shop.
That's why the most useful thing you can do at the counter is ask one question:
Has this been frozen for parasite destruction, or is it an exempt species?
A good fishmonger will answer clearly: it was frozen at sea, it's farmed salmon, it's large tuna. A vague answer, or "it's very fresh", is not good enough. Freshness has nothing to do with parasites.
Why freezing matters, and why your freezer isn't enough
Some wild fish carry parasites, the best known being Anisakis larvae, which can cause illness if eaten alive. Vinegar, salt, lemon juice, soy sauce and wasabi don't kill them. Only thorough cooking or adequate freezing does.
Food-safety rules set out the freezing needed:
| Rule | Freezing requirement |
|---|---|
| UK and EU | −20 °C or colder in every part of the fish for at least 24 hours, or −35 °C or colder for at least 15 hours |
| US FDA Food Code | −20 °C or colder for 7 days in total, or −35 °C until solid and then 15 hours at −35 °C, or −35 °C until solid and then 24 hours at −20 °C |
The time only starts once the centre of the fish reaches temperature, and a thick piece takes much longer than a thin fillet. A typical home freezer is designed to run at −18 °C, which is warmer than any of these standards. It's also opened every day and freezes slowly. The safest approach, and the one professionals use, is to buy fish that has already been commercially frozen, rather than relying on a domestic freezer. If you do freeze at home, check with your fishmonger and your national food-safety agency first.
Exempt species
Some fish are treated differently. The large tuna species (bluefin, bigeye, yellowfin and albacore) are exempt from the freezing requirement under US rules. Farmed fish raised on parasite-free feed, notably farmed Atlantic salmon, can also be exempt, and this is why farmed salmon became the standard raw salmon. Wild salmon is not exempt. Rules differ slightly between countries, so if in doubt, ask.
"Previously frozen" is a good sign. Many people avoid it, but for raw fish it's reassuring. Commercial blast-freezing is fast, very cold and done soon after the catch. A "fresh, never frozen" label on fish meant for sashimi should make you ask more questions, not fewer.
Where to buy
- Japanese and other Asian grocers are often the best option. Many sell vacuum-packed blocks of tuna and salmon (saku) that were frozen for raw use, sometimes still frozen.
- Specialist online suppliers ship frozen fish with a written freezing statement. Read it before you order.
- A good independent fishmonger will understand the question and may freeze fish to specification if you give notice.
- Supermarket packs vary. If the label says it's suitable for raw consumption or was previously frozen, that's a genuine signal. If it says nothing, assume it isn't treated and cook it.
- Your own catch, or fish with no clear cold chain: cook it.
A useful trick is to buy tuna or salmon blocks still frozen and thaw them yourself, overnight in the fridge. That way you control the thaw and know how the fish was treated.
How to judge quality at the counter
Freshness won't make untreated fish safe, but it decides whether your sushi tastes clean and bright or tired.
Blocks and fillets
- Colour: even and clear. On tuna, a broad brown band at the edges or a rainbow sheen means oxidation and age.
- Texture: firm and slightly tacky, never slimy. The muscle segments should be tightly joined, with no gaps.
- The tray: no liquid pooling. Weeping usually means a poor freeze or a careless thaw.
- Smell: clean and faintly of the sea. A strong "fishy" or ammonia smell means no.
Whole fish
- Clear, bright, full eyes, not sunken or cloudy.
- Bright red or deep pink gills, not brown or grey.
- Flesh that springs back when pressed, and a firm, intact belly.
- Tight, shiny skin with a thin, clean layer of slime.
Getting it home and handling it
- Buy fish last on your shopping trip and carry it in a cool bag with an ice pack.
- Refrigerate it at once, ideally at 0–4 °C, in the coldest part of the fridge, wrapped and on a tray below ready-to-eat food.
- Use it soon, ideally the day you buy it, and follow the supplier's use-by date.
- Keep raw fish separate: its own board, clean knives, clean cloths, and hands washed before and after.
- Work quickly. Take the fish out only when you're ready to slice, and put it back as soon as you've finished. Eat assembled sushi promptly and don't leave it at room temperature for long.
For slicing, a long, sharp knife and a single drawing stroke give the cleanest cut. Our guide to five essential knife cuts is a good place to practise the basics.
Who should avoid raw fish
Health authorities give specific advice for people who are pregnant, elderly, immunocompromised or cooking for young children. In some cases that means avoiding raw fish altogether, in others extra precautions. Check your national guidance. Cooked and vegetable sushi, such as Ebi Nigiri made with cooked prawn, Tamago Nigiri or cucumber rolls, are the easy alternative.
Once you have good fish, the classic ways to enjoy it are simple. Maguro Sashimi and Sake Sashimi in The Art of Sushi are just carefully sliced tuna and salmon. The book's fish-safety chapter covers each species, with its own notes, in more depth. When you're ready to put the fish on rice, start with our guide to making sushi rice at home.
Questions people ask
Can I use supermarket salmon for sushi?
Only if the label or the counter confirms it's suitable for eating raw, which usually means it's farmed and handled for raw use, or previously frozen to the required standard. If the pack doesn't say, cook it.
Does freezing ruin the texture of fish?
Commercial blast-freezing does very little damage because it's fast and very cold. Slow freezing in a home freezer forms larger ice crystals and can make the flesh softer and wetter. That's another reason to buy fish already frozen.
How long can I keep fish before making sushi?
As briefly as possible. Buy it on the day, or the day before at most, keep it at 0–4 °C and follow the supplier's date. Once it's thawed, don't refreeze it.
Does wasabi or vinegar make raw fish safe?
No. In the amounts used in sushi, neither wasabi, vinegar, soy sauce nor ginger kills parasites or makes up for poor handling. They're there for flavour.