Buying fresh seafood is important, because the taste and texture of fish and shellfish diminishes quickly in comparison with other foods.
A few hints and tips to consider when buying seafood to cook at home:
Chilled products (raw)
Odour: Seafood products should possess a pleasant 'marine' smell - similar to the aroma experienced from smelling fresh seaweed. They should not smell strongly 'fishy' or have any unpleasant odours - if they do, it is a sign that it may already have passed its best.
Flesh: The flesh of fish should be firm to the touch and shiny in appearance. The flesh of white fish should be translucent and the flesh should be free of any defects such as bruises, blood clots or parasites. There should be no sign of 'gaping' - meaning the flesh should be firm and compact and not exhibit any signs of ragged gaps. When buying fillets look out for neatly trimmed fillets and a white translucent appearance.
Whole fish: The skin of whole fish should be bright and shiny, with any colour variation very clear to see. Fish eyes should be convex, with a shiny black pupil. Where gills are still present on a whole fish, these should be bright red in colour. The gut cavity of whole fish should be clean, and the fish should be dry, not sitting in any water.
Smoked fish: Smoked fish should look glossy and possess a fresh smoky aroma. Smoked fish should always be stored separately from raw fish in the refrigerator. It's also important to remember that hot smoked fish is a 'high care' product and should be kept covered and stored at the top of the refrigerator.
Shellfish: When selecting shellfish, choose shells which are tightly closed and without any gaps or cracks - discard any shells that are open prior to cooking. When storing molluscs such as mussels, and live crustaceans, they should be covered with a damp cloth (or seaweed), with a lid kept on the box to avoid dehydration - this also helps to keep any excessive chill off the products. The ideal storage temperature is 6-8°C, but products should never be put directly in front of any fans blowing chilled air. Always pick up live crustaceans by the body, not the claws or tail, and treat them carefully - dropping, throwing or skidding any storage boxes across the floor will stress and weaken the shellfish. Oysters should be stored cup-side down to retain their fluid.
Surface: The surface of frozen seafood products should be free of any sign of freezer burn, which usually appears in the form of opaque, dry sections on the surface. Any protective ice glaze present on the product should be intact and not cracked.
There should be no sign that the product has been partially thawed and then re-frozen. A possible indication of this can often be if there is an excess amount of ice crystals loose in packaging or on the product itself.
The eating qualities of seafood (including texture and flavour) vary widely between different species and when cooked you should taste the flavour characteristics for the particular species. If the seafood is spoiled, the flavours will typically become sour, bitter or rancid. As a general rule, the texture of seafood should be firm and juicy. Seafood which has been frozen then thawed properly should be indistinguishable from fish that has never been frozen. If something has gone wrong during the freezing and thawing process, it is often indicated by texture changes - such as the flesh being either too wet and mushy or too dry.
While readily available, fantastic to eat and relatively easy to prepare, one considerable issue to consider with all forms of fresh seafood is that it starts to spoil quickly. While it is impossible to prevent this natural spoilage process, good temperature control and handling can greatly slow down the rate of spoilage and ensure the product is of as good quality as it can possibly be.
To maintain shelf life and quality, seafood should be constantly stored in chilled conditions, via the use of either ice or refrigeration. Even a short amount of time at room temperature will affect seafood's quality and reduce its shelf life, so this should be avoided or kept to an absolute minimum. As with the storage of most other fresh foodstuffs, the lower the storage temperature, the better.
Certain fish species, including tuna, mackerel and herring, are also susceptible to the formation of histamine at elevated temperatures - for such species, storage at temperatures lower than 4°C is especially important.
Humane handling is an important issue to consider with regards to live shellfish:
They should be handled carefully. Do not allow them to dry out and never drop them as this causes physical shock. Ideally, live shellfish should be stored at consistent temperatures, as extreme changes in temperature can cause thermal shock.
When storing chilled fish in a refrigerator, always cover with plastic overwrap to prevent any drying out. Ice can also be used in conjunction with refrigeration to reduce product temperature and maintain shelf life. If using ice, ensure that excess melt water is removed periodically, so that the fish does not stay in contact with any water. However, there are some exceptions and tuna, salmon and smoked fish products should not be directly iced.
As with all foods, cooked and raw seafood should always be stored separately.
If you adopt correct freezing procedures, it is perfectly possible to provide the same eating experience with frozen and thawed seafood as with fresh chilled fish that has never been frozen. To maintain the integrity of the product, the freezing process should be undertaken as quickly as possible and at as low a temperature as possible. If you freeze a chilled product yourself, it should be good quality and within the range of its noted shelf-life. Frozen products should be clearly labelled and used in date order. Wrap well in protective packaging to avoid exposure to air which can cause freezer burn and damage the product. Check your frozen seafood periodically to ensure it shows no sign of freezer burn - and discard anything that shows signs of damage.
The thawing process should be done using careful control of temperature and not attempted too quickly - overnight in a refrigerator is ideal. Put frozen products on a plate or tray, cover with plastic overwrap and place them in the bottom section of the refrigerator to thaw slowly. Any excess melt water should be removed. When you eventually remove thawed seafood from the refrigerator you can treat it in the same way as chilled fish.
For more information about receiving The Seafood Guide, contact Denise Day on 01472 252300 or Denise.Day@seafish.co.uk