How to cook fish and shellfish safely

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• Types of fish 
• Shopping for fish 
• Storing fish 
• Preparing fish 
• Cooking fish 
• Fish and shellfish allergies 
• Advice for pregnancy, young children and older people 

Types of fish

Seafood can be broadly classified into three types: oily fish, white fish, and shellfish.

• Oily fish such as salmon, mackerel, fresh tuna, trout, sardines, and herring are rich in vitamins A, D, and E. They are also an excellent source of omega-3 fatty acids, which can protect against heart disease and stroke. Omega-3 fatty acids are important during pregnancy for eye and brain development of the baby. 
• White fish, including cod, plaice, whiting, haddock, sole, and hake, tends to be lower in fat, making it a lean source of protein.  
• Shellfish, including crustaceans (such as lobster, crab, and prawns) and molluscs (such as mussels, clams, oysters, squid, and snails), can be a healthy addition to your diet but require specific handling and cooking precautions to ensure safety. 

Health professionals recommend that we eat two portions of fish per week, including one portion of oily fish.

Shopping for fish

You can buy fish in different forms:

• Fresh: Fresh fish is full of flavour and quick to prepare and cook.
• Frozen: Frozen fish (without coatings) has the same nutritional content as fresh fish. Fish that has been breaded, battered, or pre-sauced often contains added salt and fat, so check the labels and choose those with the lowest amounts.
• Canned: Keep canned fish like tuna or sardines as a store cupboard essential. Choose fish in mineral water rather than brine or oil for a healthier option.

What to look for when buying fresh fish

When shopping for fish, look for these signs of freshness:

• Smell: Fresh fish should have a mild, ocean-like scent. A strong, fishy smell suggests it’s past its best.
• Eyes: The eyes should be clear, bright, and slightly bulging, not cloudy or sunken.
• Gills: Gills should be bright red or pink, not brown or slimy.
• Skin and scales: These should be glossy and moist, not dry or flaky.
• Flesh: The texture should be firm and bounce back when pressed.
• Shells: When shopping for fresh shellfish, look for tightly closed shells. Avoid shellfish with open, cracked or broken shells. 

Storing fish

• Fresh fish: Buy fresh fish as close as possible to when you plan to eat it and store it in an airtight container or covered plate in the fridge. Fresh fish should be eaten within two days.
• Frozen fish: You can store fish in the freezer for several months. Follow the instructions on the package and defrost safely in the fridge before cooking.

Preparing fish 

• If you are using frozen fish, defrost it safely in the fridge for about 24 hours. Avoid thawing at room temperature to prevent bacterial growth. 
• Wash your hands thoroughly before and after you handle raw fish to prevent cross-contamination. 
• Keep raw fish separate from foods that won’t be cooked, such as salads or fruits. 
• Use separate utensils for raw and cooked fish. 
• Wash worktops and cutting boards and utensils with hot soapy water after preparing seafood. Always clean as you go when preparing raw fish and shellfish. 

Cooking fish

Once you’ve chosen your fish, there are plenty of ways to cook it:

• Grilling: Try Grilled Cajun salmon
• Frying: Try Pan fried pesto cod
• Roasting: Try Fish goujons with potato wedges
• Baking: Try Baked cod with lemon and olive oil
• Poaching: Gently simmer fish in water, broth, or milk until cooked through and flaky.
• Steaming: Place fish in a steamer over boiling water and cook until tender
• Stewing: Try Spicy fisherman's stew

Visit our recipe section for more fish recipes.

Health tip: We recommend baking or grilling, as frying, especially in batter, significantly increases fat content. Try adding a squeeze of fresh lemon instead of salt for a simple and delicious flavour boost.

Fish and food safety

• Whole fish can be cooked to preference, even slightly pink in the middle, as harmful bacteria are usually on the surface.
• Minced or skewered fish (such as, fish cakes) must be cooked all the way through until piping hot, as harmful bacteria may be spread throughout.
• Wash hands thoroughly before and after handling raw fish to prevent cross-contamination.
• Use separate utensils for raw and cooked fish.
• If you are pregnant, breastfeeding, or planning to have a baby you should avoid eating shark, marlin or swordfish as they contain high levels of mercury. You should also limit how much tuna you eat to 1 fresh tuna steak or 2 medium cans of tuna (8oz) per week.
• Young children should also avoid shark, swordfish and marlin, and limit consumption of tuna to 1 fresh tuna steak or 2 medium cans of tuna (8oz) per week.

Fish and shellfish allergies 

• Some people are allergic to fish or shellfish. These allergies can be severe and those who suffer from them must avoid all kinds of these foods.  
• If you are preparing food for someone with a fish or shellfish allergy, remember these points: 
• Take extra precautions to prevent cross-contamination and consider preparing alternative dishes to accommodate their dietary needs.  
• Work with the person without drawing attention to their allergy; they are best placed to advise on how best you can accommodate them safely.   
• Remember that fish, crustacean or mollusc allergens can be hidden in other foods such as sauces and bastes. Always check the product label for any relevant ingredients or other allergen warnings. 

Advice for pregnancy, young children and older people 

• Vulnerable people, including older people, young children, pregnant women, and those with weakened immune systems, should avoid eating undercooked fish and shellfish. Fish is fully cooked when it is opaque and flaky. 
• If you are pregnant, breastfeeding, or planning to have a baby you should avoid eating shark, marlin or swordfish as these fish contain high levels of mercury. You should also limit how much tuna you eat to 1 fresh tuna steak or 2 medium cans of tuna (8oz) per week.  
• Young children should also avoid shark, swordfish and marlin, and limit the amount of tuna they eat to 1 fresh tuna steak or 2 medium cans of tuna (8oz) per week.