Lobsters and crabs can be kept alive if tightly packed in damp straw (to restrict movement) and kept cool, but crustaceans are sometimes difficult to keep alive and are better cooked on the day they are purchased. When they die they should be chilled (iced) immediately and cooked as soon as possible. Dead unchilled crustaceans will spoil rapidly.
If travelling a moderate distance, for example from shopping centre to home, ask the retailer to mix some ice with the seafood before wrapping it well. In summer it is advisable to keep the parcel cool in an insulated container. If travelling a long distance, thoroughly ice the fresh seafood, using the same weight of ice as seafood, and store in an insulated container which allows the melting ice to drain so that the food does not float in water.
Some Australian seafood which are harvested and processed far from retail outlets, e.g. barramundi fillets and scallop meat are only marketed frozen. These seafoods are of excellent eating quality because they are frozen while still fresh soon after catching. Quick freezing does not noticeably affect eating quality; it may cause only a very slight loss of flavour and a slight firming of texture.
Wherever possible freeze the seafood raw, completely cleaned and in meal-sized amounts so that it will be ready to cook from the frozen state and will not require thawing. It is most important to label and date mark each pack before it is placed in the freezer. Do not keep more seafood that you can use in 9-12 months.
Freeze whole fish only if you want to cook and serve it whole, otherwise it is better to freeze it as fillets or cutlets because these will freeze faster and stack more conveniently in the freezer. Rinse the fresh fillets or cutlets in clean water, making sure they are completely clean. Wrap enough pieces for one meal in plastic wrap to avoid the need to thaw more than you need; it is a good idea to separate the fillets with plastic wrap so they come apart easily when frozen. Label and date mark each pack and then place in the coldest part of the freezer to ensure fast freezing. The frozen fish cutlets or fillets should then be dipped in cold water, some of which will freeze to the surface of the fish, forming an ice glaze. The glaze helps protect the frozen food from drying out (freezer burn) and developing off-flavours (cold storage flavours).
Clean and remove inedible portions, such as the lobster’s head or the abalone shell. Wash carefully and wrap large specimens such as lobsters or crabs separately. Freeze small species, such as prawns or abalone in a the seafood completely with cold water and place the container into the coldest part of the freezer. When frozen solid, repack into heavy duty plastic bags, label and date mark. The freezing of small items into a block of ice prevents freezer burn and formation of cold storage flavours.
Seafood should not be bought to freeze at home unless it is absolutely fresh when purchased. Commercially frozen seafood is usually cheaper and better processed than home frozen food.
If your freezer can maintain a temperature of -18°C (0°F) or colder, lean seafood such as prawns, bream, whiting, snapper, lobsters and scallops will keep for 9-12 months. Fatty seafood such as mullet will only keep well for three to four months before off-flavours develop. However it is not a good idea to store undated commercial packs of seafood at home for longer than two months because you do not know how long the seafood has been frozen when you buy it.