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Cooking Temperatures by Food

Fish Cooking Temperature UK: Safe Core Temps by Species

Fish Cooking Temperature UK: Safe Core Temps by Species

Fish and shellfish require different temperature approaches to meat. Fish proteins denature at lower temperatures, meaning fish is "cooked" from a texture perspective at temperatures below those needed for meat. However, the food safety requirements still apply: pathogenic bacteria, parasites, and viruses must be destroyed through adequate cooking. The general recommendation for fish in UK food businesses is a core temperature of 63C for most species, with shellfish requiring 75C. This guide breaks down the requirements by species and preparation method.

Key takeaways

Most fin fish should reach a core temperature of 63C. Shellfish should reach 75C
Fish served raw or lightly cooked must have been frozen to -20C for 24 hours to kill parasites (with limited exceptions)
Probe fish fillets horizontally through the thickest part. For battered fish, probe through the coating to the centre of the flesh
Shellfish that do not open during cooking must be discarded

Quick Answer: Fish Should Be Opaque and Properly Cooked Through

For most fish served cooked in a UK food business, the practical safety check is that the flesh is opaque, steaming hot, and flakes easily with a fork. A probe target of 63C at the thickest part is commonly used for fin fish, while 70C for 2 minutes or 75C for 30 seconds gives a larger safety margin and aligns with general FSA cooking combinations. Shellfish and mixed dishes containing fish should normally be cooked to 75C core. If your HACCP plan uses lower-temperature service for quality reasons, such as lightly cooked salmon, it must document supplier controls, parasite controls, time-temperature validation, and corrective action.

Fish and Shellfish Temperature Guide

White fish such as cod, haddock, hake, plaice and sea bass: cook until opaque and flaking, using 63C core as a practical minimum or 75C where your HACCP plan uses the general cooking standard. Oily fish such as salmon, trout and mackerel: cook to the documented target in your HACCP plan; 63C is a common cooked-fish target, while lower-temperature service needs validated controls. Battered fish and fishcakes: probe through the coating into the centre of the fish or fishcake, not the batter surface. Prawns, scallops, crab and lobster: cook until firm and opaque, using 75C core for HACCP records. Mussels, clams and oysters cooked in shell: discard any that do not open during cooking. Fish pies, curries, soups and mixed dishes: treat as high-risk mixed food and verify 75C core.

Parasites and the Freezing Requirement

Certain fish species carry parasitic worms (Anisakis in particular) that are destroyed by cooking to 63C. For fish that will be served raw or lightly cooked (sushi, sashimi, ceviche, tartare), EU-origin legislation retained in UK law requires that the fish has been frozen to -20C for at least 24 hours (or -35C for at least 15 hours) prior to serving. This freezing step kills parasites without cooking the fish. Farmed Atlantic salmon is exempt from this freezing requirement under certain conditions, as the controlled rearing environment and feed reduce the parasite risk to negligible levels. However, wild-caught salmon and all other wild-caught fish intended for raw consumption must be frozen first. If you serve raw or lightly cooked fish, your HACCP plan must document the freezing step, the species used, the supplier confirmation of freezing conditions, and the defrosting procedure. EHOs will check this documentation, and failure to comply can result in enforcement action.
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Probing Fish and Batch Considerations

Fish fillets are typically thin, which makes probing more challenging than with meat. Insert the probe horizontally into the thickest part of the fillet, aiming for the geometric centre. For a thick fillet such as cod loin, the probe can be inserted from the side. For thinner fillets, you may need to fold the fillet or stack two together to get the probe deep enough for an accurate reading. For batch-cooked fish (such as fish and chips), probe at least 2-3 pieces per batch, selecting the thickest items. The batter or breadcrumb coating insulates the fish and can give a misleading surface reading, so always probe through to the centre of the fish itself. For whole fish, probe the thickest part behind the head, inserting the probe at an angle to reach the flesh near the backbone. This is the last area to reach temperature in a whole fish.

What to Do if Fish Is Undercooked

If fish is still translucent in the centre, not steaming hot, or below your documented critical limit, continue cooking and re-check before service. For battered fish, return it to the fryer only if the product can finish cooking without burning the coating; otherwise discard it and review portion thickness, fryer temperature, loading, or cook time. For shellfish, do not force closed mussels, clams or oysters open after cooking. Discard them. Record corrective actions for batch-cooked fish in the same way as meat: initial reading, action taken, final reading, staff member, and any equipment issue.

What to do next

Confirm freezing status for any fish served raw

Obtain written confirmation from your supplier that fish intended for raw or lightly cooked dishes has been frozen to the required parameters. Keep this documentation on file.

Probe battered and breaded fish through the coating

The coating insulates the fish and can read hotter than the flesh inside. Always insert the probe through the batter or breadcrumb to reach the centre of the fish fillet.

Train staff on shellfish discard criteria

Ensure all kitchen staff know that mussels and clams that do not open during cooking must be discarded. Do not force them open. This indicates the shellfish may have been dead before cooking.

Common mistakes to avoid

Mistake
Serving raw fish without verifying the freezing step
Instead
Raw or lightly cooked fish must have been frozen to -20C for 24 hours (or equivalent) to destroy parasites. Obtain supplier documentation confirming this.
Mistake
Probing the surface of battered fish instead of the centre
Instead
The batter reaches high temperatures quickly while the fish inside may still be cold. Push the probe through the coating to the geometric centre of the fillet.

Frequently asked questions

What temperature should fish be cooked to in the UK?

Most cooked fin fish should be opaque, steaming hot, and flake easily. Many food businesses use 63C core for fin fish, while 75C gives a wider safety margin and is appropriate for shellfish, fishcakes, fish pies, and mixed dishes.

What is the 10 minute rule for fish?

The 10 minute rule is a cooking guideline often used by chefs, not a UK food safety legal limit. In a food business, use visual checks plus your documented HACCP control: probe the thickest part and verify the fish has reached the required internal temperature.

What temperature do chefs cook fish at?

Chefs may cook some fish to lower temperatures for texture, especially salmon or tuna, but a hospitality business needs a validated HACCP plan if serving lightly cooked fish. For standard cooked fish service, use a documented core temperature and verify with a probe.

Can I serve salmon rare or medium in a restaurant?

Lower-temperature salmon service is possible with documented HACCP controls: sourcing from reputable suppliers, confirmed freezing history for parasite control, and precise temperature monitoring. Most food safety authorities recommend 63C as the standard for commercial kitchens.

Do I need to freeze fish before serving it raw?

Yes, with limited exceptions. UK law requires that fish served raw or lightly cooked has been frozen to -20C for at least 24 hours to kill parasites. Farmed Atlantic salmon may be exempt under certain conditions, but wild-caught fish always requires the freezing step.

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