The body needs for growth and health a right proportion of several food materials. The chief ones are proteins (for building flesh), heat and energy material, and mineral matter for the building of bones and teeth, and vitamins for growth and resistance to some diseases.
Fish and most other sea-foods are good proteins—they are tissue builders and they are rich in mineral matter. Fish may take the place of meat, cheese, or eggs, in the diet.
It may be stated as a general rule that the fish should be used as soon as possible after being caught. A few watery fish—as red cod—are improved by being sprinkled with salt for a few hours before using. This makes the flesh firmer, and extracts some of the water.
The eyes of fresh fish are bright and full. The flesh should feel firm, not flabby. The smell should not be unpleasant. In Butter or Kelp fish the bone is green, and the brightness of the colour denotes the freshness of the fish.
In Moki the bone is some-times dark, almost black, the colour depending on the feeding ground of the fish. Choose fish in season.
The nutritive value of a fish at its best is double than that of the fish in poor condition. Shell-fish may be bought alive. If the shell is open or partly open the fish is dead or dying, and should not be used as food.
Lay the fish on several thicknesses of newspaper—hold the fish by the tail—and by passing the blade of a knife over the fish from tail to head, remove the scales; with a pair of scissors remove the fins, tail, etc.
Keeping the fish still on the paper insert the point of the scissors at the vent, and cut open the fish to the head. Turn back the flap and with a knife remove the inside on to the paper. Roll up all waste material in the paper and burn or bury at once.
Thoroughly clean inside and outside of fish with a damp cloth. If the scales are hard to remove dip the fish in hot water for a second before scaling.
It is a mistake to wash fish much, or allow it, as a rule, to lie in water for any length of time. Fresh-water fish having a muddy taste or smell, may be soaked in salt and water for a short time to remove this, but the soaking also extracts some of the nutriment.
If an oversupply of fish is on hand, cook as much as can be conveniently used. Any left-over cooked fish may be served next day re-heated or as a salad. The surplus should be potted, pickled, or salted at once. It is only under exceptional conditions that fresh fish may be kept uncooked for any length of time.
FLAVOURING AND SEASONING
Flavourings and seasonings should be used to enhance or increase the natural flavour of a food and not to disguise it. In the majority of cases sliced lemon is served with fish, irrespective of the method of cooking.
Allow half to one slice of lemon for each serving. Over flavouring and under seasoning are two common faults of the inexperienced cook.
Lemon rind and juice, vinegar, bacon, parsley, tomato, onion, horseradish, nutmeg, mace, cloves, peppercorns, may all be used in turn, and if used with discretion will, in addition to salt, increase the typical flavour of the various marine foods.