EOOD SCIENCE and TECHNOLOGY NOTES E ~So

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VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY

Slacktburg, Pirtttnia 24061

EOOD SCIENCE AND TECHNOLOGY NOTES e ~so

SALTING FISH p Oy@ By Sharon R. Turner

The next time you come home with a Salting is usually done by one of sizable catch of fish, you might want two methods, brine salting or dry- to consider preserving them in an en- salting, In the brine salting pro- tirely different manner. You probably cess the fish are salted and layered never considered salting fish, but in a container which holds the fish the procedure is simple and is one in the brine liquor that seeps from of the oldest methods of food preser- the salted fish. In the dry salting vation. Our earliest records of food method the brine liquor that escapes preservation practices include using from the fish is allowed to drain salt for preserving fish. Salt has away. Though commercial salting of long been used both as the primary fish has declined significantly in preserving ingredient, and in combina- this country, a small quantity of tion with other methods such as dry- fish are still salted. Most of this ing and smoking. is exported to the Caribbean, South America, and southern Europe. In recent years salting, as a preservation technique has become less popular because of development of quick freezing preservation methods Mhy Salt Slows OownSpoilage for fish. Frozen fish have much the Common salt or sodium chloride, if same flavor as fresh fish, while present in sufficient quantities, will salted fish have a distinct flavor slow down the processes that occur in derived from the salting process. fish during spoilage. Spoilage is

The Virginia CooperativeExtension Service by law andpurposeis dedicated to serveall peopleon an equaland nondiscriminatory basis, An Equal Opportunity/Affirmative Action Employer. An EducationalService of the Virginia PolytechnicInstitute and State Uniuersity, Virginia's Land-GrantUni uersity, with US, Departmentof Agricultureand Commerceand Local GovernmentsCooperating, brought about by two causes: ! sulfates!. These impurities give the autolysis, the deterioration of the fish a firmer white flesh which has bodily tissues after death by enzymes provento be moremarketable. They which are part of the biological make- also give the fish a sharp bitter up of the organism; ! deterioration taste characteristically associated due to bacteria already present in with salted fish, the fish, which grow rapidly under If these impurities are present in favorable conditions and produce en- sufficient quantities, the fish may zymeswhich break downthe fish tis- spoil becausethe absorption of salt sues, Usually the quantity of bac- is inhibited. teria in the body of a fish is small, but they are often introduced through ! The thickness of the flesh of handling, cleaning, washing, etc, Most the fish can also slow the penetra- of these enzymesand bacteria are de- tion of salt. If fish are salted stroyed or rendered inactive in a con- whole or round beheaded and envis- centrated solution of salt. cerated!, the enzymes contained in the fish's body may cause the fish As salt is being absorbed into the to spoil before salt is taken into fish, the bacteria and the enzymes the flesh in sufficient quantities are still active, and their growth to arrest spoilage. Since most of and activity continues until a certain the enzymescausing autolysis are in level of salt concentration is reached. the blood and organs of the fish, At that level, bacterial growth and whole fish are more susceptible to activity are arrested and spoilage this effect. Enviscerated fish prevented. The presence of more than should be thoroughly cleaned to min- 6". salt in solution in the tissue of imize this effect. the fish retards both autolytic and bacterial decomposition. If the up- ! Likewise, if the fish is not take of salt is slow, the fish can fresh when it is salted, the enzymes becomespoiled before this level is and bacteria may have caused the flesh reached. to deteriorate to such a degree that the rate of salt absorption is slower than the decomposition of the fish. Factors Affecting Salting Process The fat content in fish significantly Several factors affect the rate of affects the salting process. Fatty salt absorption into the fish. These fish do not as readily absorb the salt include ! the purity of the salt; and therefore bacterial growth may not ! the thickness, ! freshness and be slowed quickly enough to prevent fat content of the fish; ! the tem- spoilage. perature; and ! the care and clean- ! Spoilage can also be enhanced iness used in handling the fish. or retarded by the temperature during ! If a solution of pure sodium salting. At very high temperatures chloride is used, fish do not acquire bacterial growth may be so rapid that the bitter taste commonly associated the fish become spoiled before they with salted fish, but they become absorb enough salt. Even after fish soggy and yellow. Fish salted with are salted, they deteriorate much more pure sodiumchloride are most like rapidly at high temperatures than at fresh fish when freshened soaked cool ones. Heavily cured fish those with water before preparing!, but which were cured in a concentrated most commercially salted fish are pre- solution! may be preserved at high pared in salt containing impurities temperatures for only a few days but calcium and magnesium salts and can be held at lower temperatures much longer. ! If the fish are not handled same species. Also the statistics and stored properly under sanitary are based upon relatively small conditions the initial bacteria count samples. The following lists can in the salting process maybe quite serve as a general guide. Table I! high, Also rough handling can tear and bruise the flesh of the fish and Fish have been categorized as lean consequently shorten the amount of when the percentage of fat is less time the fish can be held before than 2.5e, moderate between 2.54 and spoiIage. 6.54, and fat if over 6.5't. Exception for species within a common name have been noted. Changes Due to Salt Absorption

Salt preserves fish by extracting Table 1. Fat Content of Fishes water from the tissues and replacing it with salt. This absorption occurs until the concentration of salt in Some FAT fish are: the tissues is the same concentration Butterfish Chinook salmon as in the solution surrounding the Freshwater eels Sockeye salmon fish, or until it reaches an upper Atlantic herring Shad limit of about 20+. Oncethe quantity Pacific herring Lake trout of salt in the fish rises above 9't, Atlantic mackerel Rainbow trout irreversible changes take place in Sablefish Whitefish the muscle proteins. At this point Some MODERATELYFAT fish are: the fish is said to be "struck through." The inner flesh loses much of its trans- Albacore Mullet Blue fish Coho salmon lucent appearance and stickiness. Carp barbus! Chum salmon Carp cyrpinus! Pink salmon Indian carp Sardines Select Fish Carefully Chub Scup Conger eels Smelt Before beginning the salting process, Lake herring Swordfish it is important to consider the char- Pacific mackerel Brook trout acteristics of the fish you wish to Mackerel scombermorus! Dolly Varden Mackerel auxis! trout salt. Somefish have a higher fat Mackerel scomber! content and should probably be salted Bluefin tuna using the brine rather than the dry- Some LEAN fish are: saIting method, since the brine method Snake eels Haddock gives a more consistent distribution Fimbriated herring Hake of salt. Fatty fish do not as readily Indian mackerel Halibut absorb salt and are thus more likely Pompanoor permi Perch to spoil. Bigeye tuna Pike Yellowfin tuna Pollock Once the fish are salted, fat tissues Carp cirrhina! Porgies are susceptible to rancidity due to Cod Rockfi sh oxidation, so fatty fish need to be Croaker Snapper Flounder Soles kept in cold storage or in a manner Grouper that prevents them from oxidizing, Whiting Such handling is more successful or easier! with the brine method. Salt Purity Is Important It is difficuIt to classify fish accurately based upon fat content be- For salting, the purest salt with cause this quantity varies considerably the finest grqin available should be from one fish to another within the used. Salt which is virtually chemi- cally pure less than l% impurities! results in fish with a milder, more the brine, the fish can be scored pleasant flavor, which do not need at 1-2 inch intervals along the prolonged freshening. The finer the length. When scoring the flesh, the salt, the more rapidly the brine forms, skin should not be cut. Large fish and thus the more rapidly the flesh is can be filleted and thick-skinned; penetrated with salt. Standard curing spiny or large-scaled fish should salt is available from salt companies, be skinned before brining. butcher supply firms, and often rural The prepared fish should be washed feed stores. thoroughly in fresh water and then For home preparation the brine method soaked in a brine of 1/2 cup of salt or gaspe is becoming more popular. in one gallon of water for 30-60 minutes. This will draw any blood from the fish and cut any remaining The Heavy Cure Method skin slime.

Most small or medium sized fish are After the fish are drained for 5-10 prepared for brining in the same man- minutes, they should be dredged or ner: they are scaled, beheaded, en- coated! with salt. The fish are now viscerated, and split along the back- ready to be placed in the container bone. To facilitate penetration by in layers. A good container for brining is a stoneware crock. Put a layer of salt in the bottom, skin side down or backs down!if whole. Add a thin layer of salt and another layer of fish at right angles to the preceding layer. Do not let the fish in a single layer overlap any more than is nec- essary. Stagger the layers so that the fish are distributed as evenly as possible. Place the top layer of fish skin side up or backs up! and add a generous amount of salt.

The amount of salt used for the entire salting should be between a quarter to a third the weight of the fish, This amount is dependent upon the purity of the salt, the size of the grain, the temperature Sp]it Fish warm weather requires more salt!, and the size and fat content of the fish. Put a loose wooden cover on the top layer and a weight on top of that to compress the fish and force out the brine. Small fish will generally be com- pletely brined in about 48 hours, while larger fatter fish may take 10-14 days. When brining is completed, scrub the fish in a fresh full-brine solution one quart of salt for each gallon of water! with a stiff brush. Then repack in the crock, with a light sprinkling of salt between layers. Make sure the layers are well pressed.

Fill the crock with a fresh full- brine solution and store in a cool dark place. The fish will keep like this for about 9 months, if the brine is closely watched. At any sign of fermentation the fish should be washed and repacked,

Light Cure The procedure for a light cure is the same, but it can be used only for fresh less than 48 hours old! lean fish and only in cool temperatures. The amount of salt used for a light cure or gas~e is in the proportio~ of I to 10. This may vary, as in a heavy cure, depending on the temperature, the type of fish, and the salt should be removed and put in a container and stored in the refrigerator. They can be kept chilled like this for a short period of time or they may be dried and chilled. Light-cured fish are yellow when removed from the brine; when dried, they have amber-colored translucent flesh and taste somewhat like cheese. Light-cured fish cannot be kept nearly as long as heavily cured ones. Curing Herring Dry Sal ting Herring are handled differently. The dry-salting process requires They should be brined immediately more care and effort than the brine after being caught not held on ice!. method. And though fish particularly They can be brined whole, gibbed, or fat fish! are more likely to spoil thoroughly cleaned. during the dry-salting process, once the fish are "struck through" drying Traditionally they were gibbed. In decreases the likelihood of spoilage. this process the herring is held with This is the traditional method for its back to the palm, the head between curing cod in the New England area the thumb and forefinger, leaving the and North Atlantic. Dry-salted cod, throat clear. A short bladed knife cusk, haddock, and mackerel can be is inserted under the gill cover. With bought in many parts of the country the edge of the blade toward the stom- ach, a sharp twist upward and outward in wooden boxes or tubs. removes the throat, pectoral fins, Fish to be dry-salted should be gills and main gut in one operation. bled immediately when caught, Cut The strong taste associated with the throat and remove the gills, and whole or gibbed fish has become less ice the fish; when ready to salt, popular, so it is preferable to thor- clean the fish and cut it along the oughly clean the fish removing all backbone so the flesh lies flat. the viscera and the head. Clean the fish throughly, inside and out, removing all traces of black skin, Thoroughly scrub the herring in a blood, etc. Wash in a brine of one brine solution to remove scales and cup of salt. for each gallon of water. leach out the blood. Then drain. Scrub the fish to be sure it's clean Layer the herring in the crock with and then drain well. Remove as much their backs down, except the top moisture as possible. layer which should be backs up. The brine solution of the herring should Using the finest salt available, be replaced every two months. dredge the fish in salt. Put a layer of salt in the bottom of the container cheesecloth over the fish so flies do to be used. The container should drain not spoil them. They should be turned well, allowing the brine to flow away several times the first day. from the fish and not remain trapped in the bottom. The fish should be The screens must be brought indoors placed skin side down and salt spread at night for the moisture could allow between each layer of fish. The top mold to grow on the fish. If the layer should be placed skin side up weather turns bad and the fish can' t and then thoroughly salted, The usual be taken outside, the fish shou1d be proportion of salt to fish is 25-33t salted lightly. This salt should be of the weight of the fish. More or brushed off when they are again put less may be needed depending upon the out of doors. temperature, the salt used and the Rapid drying produces a superior condition of the fish. A top with a product with a clear colored flesh. weight on it can facilitate the flow The best way to tell when the fish of brine from the fish. have dried sufficiently is to pinch Usually the fish should be 1eft for the thick section of the flesh. If about 48 hours to a week, depending your fingers don't leave an impression, upon the humidity and the temperature. the fish are ready for packing. Under warm and dry conditions, the Dry salted fish are usually wrapped time could be shorter. in wax paper and packed in this wooden Once the fish are "struck through" boxes or tubs. At home if these are they should be removed from the salt unavailable you can wrap the fish and and scrubbed well witk a brine solu- place them in the freezer, Even in tion so that no salt remains on the wooden containers with airtight lids surface. Drain the fish well, They they should be kept in a cooI, dry are now ready to be dried. place. Drying should be done in the shade For the maj ority of recipes and sunlight will discolor the fish! in tastes! dry salted fish should be an area with free-flowing air cirula- freshened soaked in fresh water from tion. A hardware-cloth screen raised one ha1f hour to twelve hours before on legs a few feet off the ground can preparing!. Salted fish which have be used, The fish should be p1aced been freshened can be used in nearly skin side down on the screen. Prop any standard recipe calling for fish or fillets. Other Publ i cati ons

Other nutrition-related FST Notes which may be obtained free! from the Department of Food Science and Technology, VPI 6 SU, or from local Extension offices:

Smoking Fish At Home - A Step By Step Guide, by Cherrie L. Kassem

History Of Colonial Foods In Virginia, by William R. Hess, Jr.

Government Guidelines On Nutrition - A Review Of The Dietary Goals, by Cherrie L. Xassem.

Food and Facts - A Consumer's Guide To The Code Of Federal Regulations, by John W. Long.

Food Additives, by Dr. Anthony Lopez

Making Cottage Cheese In The Home, by Paul M. Large.

Squid - An Underutilized Species, by Chieko Hebard and Sharon R. Turner.

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