Detailed Guide to Shark Processing Techniques: Master the Correct Handling Methods

Sharks, also called "jiao," belong to the subphylum Vertebrata, class Chondrichthyes. They are divided into the families Hexanchidae, Heterodontidae, Lamnidae, Rhincodontidae, Triakidae, Carcharhinidae, Sphyrnidae, and Squalidae. The body is spindle-shaped, and the skin bears dermal denticles resembling sandpaper, which is why they are also called "sand fish." There are 5-7 gill slits on each side, with 5 being the most common. The broadnose sevengill shark of the family Hexanchidae has 7 on each side. There are 1-2 dorsal fins, with two being the most common; the broadnose sevengill shark has one dorsal fin (located toward the rear of the body). The caudal fin is generally well developed, mostly heterocercal, and in a few species the anal fin is absent. Some are oviparous, and some are ovoviviparous. They feed on fish, cephalopods, or crustaceans, and all are ferocious by nature. They live in the sea, and a few species also enter freshwater. China has more than 70 species of sharks of relatively high economic value, and common ones include the requiem shark, basking shark, starspotted smooth-hound, spiny dogfish, broadnose sevengill shark, tiger shark, and hammerhead shark. Shark meat is edible, the skin can be processed for food, made into leather, or processed into fish glue; the fins can be made into shark fin, the lips can be made into fish lips; some cartilage can be processed into "minggu" (shark cartilage); the liver contains relatively large amounts of vitamin A and vitamin D, and is a good raw material for producing medicinal cod liver oil pills or emulsified cod liver oil; the other internal organs and bones can be made into fishmeal for feed and fertilizer.

(1) Dried Shark

Shark meat contains urea, so when eaten fresh it must undergo a certain preheating treatment to let the ammonia volatilize. The traditional processing method is to process shark meat into salted dried product; after salting, not only can the urea be removed, but the flavor is also very delicious when eaten. For the basking shark, which has loose flesh, coarse fibers, and high water content, as well as certain sharks containing more pure meat, it is generally not suitable to process dried product; in the past they were generally handled fresh, and now most are processed into frozen products. The processing method for salted dried shark product is introduced below:

1. Processing of Large Sharks

Sharks weighing more than 15 kg each can be processed into salted dried meat slices, with the following steps:

(1) Cutting off the fins: Use seawater to wash away mud, sand, and other dirt attached to the fish body. Lay the fish body on its side, first cut off the pectoral and pelvic fins. Then cut off the dorsal fin; finally cut off the pectoral and pelvic fins. When cutting the fins, cut close to the fin base, and the knife path should be parallel to the base of the fin. When cutting the caudal fin, do not cut off the entire tail completely; instead, cut diagonally close below the caudal vertebrae on one side. Remove the flesh attached to the base of each fin with a knife, rinse with seawater to remove blood and dirt, and then spread them out to dry. In summer, when temperatures are relatively high, to prevent spoilage, before spreading them out to dry, dip the base of the fins in salt water (use saturated brine or nearly saturated brine), with a dipping depth of about 1 cm. When fully dried, they become the finished product known as original fins (also called green fins).

(2) Splitting open and removing the viscera: Insert a fish knife from the anus into the abdominal cavity, cut along the midline of the belly toward the head up to the throat, then reverse the knife and cut from the anus to the base of the tail. After the belly is opened, take out the liver and other internal organs in sequence and store and handle them separately, then rinse the blood and dirt in the cavity clean with clear water.

(3) Skinning: Use a fish knife to skin; with one hand pull the fish skin and with the other hold the knife to peel off the skin layer, peeling from the belly toward the back, and peel open the head skin. After the entire sheet of fish skin is removed, cut off the fish head. When skinning, pay attention to keeping the knife cut steady, do not tear the skin, and do not let fish meat remain on the skin, which would make it difficult to dry and cause maggots, reducing the quality of the fish skin. Soak the removed fish skin in clear water for about 20 hours, then rinse it clean; after fully drying it becomes fish skin, which can be used for food, made into leather, or processed into fish glue.

(4) Cutting into sections: Insert the knife at the joints of the vertebral column and cut the fish body crosswise into several sections, with each section preferably about 30 cm long. After cutting into sections, wash off blood and dirt with seawater, then cut into strips.

(5) Cutting into strips: Use a knife to cut the fish sections lengthwise into meat strips, and remove the vertebral column (the spine of the broadnose sevengill shark can be used to make "minggu," while the spines of other species can be used to make fishmeal). The specifications of the meat strips are: length maintained as is, about 30 cm, width about 6 cm, thickness about 3 cm. After cutting into strips, if there is still blood and dirt, it still needs to be rinsed with seawater, and then pickled.

(6) Pickling: After the shark meat is cut into strips, pickle immediately, with a salt amount of about 15%; in cloudy and rainy weather it can be appropriately increased. The pickling method is: first place the meat strips on a weighed pile of salt, and use your hands to apply salt so that salt grains evenly adhere to the meat strips. First sprinkle a thin layer of salt at the bottom of a vat (barrel), then arrange the fish strips neatly in the vat or wooden barrel. With each layer of meat strips, sprinkle a little separating salt, and finally seal the top with salt. After about 10 hours, press with stones so that the brine submerges the meat strips. After 1-2 days of pickling, they can be taken out and washed.

(7) Washing and scrubbing: Soak the meat strips in clear water and carefully rub the surface of each strip by hand or with a soft cloth to remove attached salt crust and dirt. During soaking and scrubbing, excess salt can be removed. Desalting should be appropriate, because if desalted too much the fish meat is too bland and most likely to spoil when dried in relatively high temperatures and cloudy and rainy weather; if desalting time is insufficient, the surface of the finished product is prone to salt bloom, reducing quality. When you push and feel the surface of the meat strip and it feels slippery, this indicates that desalting is appropriate.

(8) Slicing: After washing and scrubbing, the meat strips are sliced. Because fresh fish meat has high water content and is relatively soft, it is difficult to cut into thin slices, but after pickling the fish meat becomes firm and is convenient for slicing, and the cut meat surface is also smooth and attractive. When slicing, place the meat strip on a cutting board and cut lengthwise into meat slices about 1 cm thick; the original thickness of the meat strip becomes the width of the meat slice. When cutting, the knife path should be steady, and the slices should be uniform in thickness.

(9) Sun drying: After slicing, place each slice on a bamboo curtain or mat, and lightly rub the meat surface with your fingers so that it becomes glossy after drying. When dried until a thin hard skin forms on the meat surface, turn them over. On the first day, turn and dry two or three times. When turning and drying, pay attention to shaping. After two days of turning and drying, they can basically reach 60-70% dryness; stack them and press flat, and after two more days dry them again until fully dry.

(10) Finished product quality requirements: The meat slices are flat and straight, the meat is firm, the color is pale yellow, and there is no salt bloom or oil burn.

(11) Packaging: Use plastic bags for fixed-quantity packaging and seal them, then pack in cardboard boxes. To prevent the plastic bags from breaking, soft paper can be used as padding between bags.

2. Processing of Small Sharks: For sharks under 15 kg (excluding juvenile sharks under 2 kg), the traditional processing method is to split them open into butterflied fillets and pickle them into dried product. The processing method is as follows:

(1) Splitting: After the mud, sand, and other impurities on the fish body surface are washed clean, place the fish on its side on the cutting board, with the head toward the person and the back ridge to the left and right. Hold the knife and cut into the back along the left side of the spine, penetrating the abdominal cavity, and push closely along the spine toward the base of the tail. Reverse the knife and cut open the skull, but the snout must not be cut open. The dorsal fin should remain on the left side of the spine (that is, above the knife), and at the same time spread the fish fillet open. Then turn the fish tail toward the person, cut off the spine at the base of the tail, insert the knife under the lower edge of the spine and push-cut from the tail to the head, and by the way turn the spine outward to the side. Finally, make one cut at each of the left and right gills to fully spread open the head. Use the tip of the knife to pick out the blood clinging to the bone on the inner wall of the belly. When splitting, the knife cuts should be correct and smooth, and the tail should remain intact. After splitting open, first remove the fish liver, then take out the other internal organs and place them separately, to be processed into by-products.

(2) Pickling: Rinse the split fish fillets clean with clear water, then place them in a pool or vat to pickle, with layer upon layer of fish and salt, and finally add a top-sealing layer of salt; no pressing stones are needed. The total salt amount is 12-15% of the weight of the fish fillets. The pickling time is preferably 3-4 days. In summer, during high temperatures and cloudy and rainy weather, the salt amount can be appropriately increased.

(3) Sun drying: Before sun drying, the pickled fish fillets must be washed clean; those with high salt content should be appropriately soaked to remove brine. When drying, it is best to hang them or place them on racks to dry. First dry the meat side, then the skin side. When dried to 60-70% dryness, take them in, stack and press, shape them, and let the moisture spread. After two days, put them out to dry again until fully dry.

(4) Finished product quality requirements: The meat is hard, the meat surface is smooth, the color is pale yellow, the splitting is correct, the knife cuts are straight, the fish fillets are flat, and there are no defects.

(5) Packaging: Pack in square baskets, or bundle and pack with straw sheets.

3. Processing of Juvenile Sharks: Juvenile sharks weighing under 2 kg each are suitable for processing into small shark meat strips. The processing method is as follows:

(1) Removing sand: Grasp the fish tail with your hand and put the fish into hot water at about 70°C, turn it a few times and take it out, then immediately scrub off the sand skin with a grass-root whisk broom until the sand skin is completely removed.

(2) Splitting: Place the fish on its side on the cutting board, with the head toward the person and the belly facing left. Grasp the gill area with your left hand, hold the knife in your right hand, and push-cut from the head close along the spine through the abdominal cavity to the base of the tail. Remove the internal organs, then cut off the fish head and remove the spine, making two pieces of meat still connected at the tail.

(3) Pickling: Use 6-8% salt, and place them layer upon layer of fish and salt into a vat or barrel. After 1 day of pickling, they can be taken out, brushed clean, and spread out to dry.

(4) Sun drying: Spread the brushed fish fillets flat on a bamboo curtain or straw board to dry. First dry the meat side, then the skin side. When half dry, cut the fish fillet lengthwise down the middle, cutting each fish into 4 fish strips, with the tail still connected, forming a palm shape. Continue drying until fully dry. During the drying process, pay attention to shaping.

(5) Finished product quality requirements: The meat strips are evenly dry, the knife cuts are smooth, the meat is pale yellow, sometimes slightly covered with white powder, but without salt bloom.

(6) Packaging: Pack in cardboard boxes or square baskets.