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What is fish processing?
Fish processing refers to preparing seafood and freshwater fish for people to consume. Since before recorded history, communities across the globe have relied on fish from marine and freshwater environments as a major food source. Ancient cultures such as the Egyptians and Greeks harvested wild fish and employed rudimentary processing techniques like sun-drying, salting, and smoking to preserve their supply.
Modern fish processing includes inspecting, washing, sorting, grading, and butchering. The four basic procedures used in the final processing of fish products are heating, freezing, controlling water activity, and irradiation. These methods extend the shelf life of fish by inhibiting spoilage and degradation mechanisms.
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Why do people process fish after catching them?
Fish are processed after catching to prepare them for consumption. Preprocessing includes inspecting, washing, sorting, grading, and butchering the harvested fish.
Final processing methods like heating, freezing, drying, chemical additives, and irradiation extend shelf life by preventing spoilage and degradation. Freezing maintains flavor and quality by halting biochemical reactions. Rapid cooling and holding at temperatures between 2 and -2 °C (36 and 28 °F) occurs immediately after harvesting.
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What are some basic steps involved in fish processing?
Fish processing involves preparing seafood and freshwater fish for consumption. Proper handling after harvesting is crucial for retaining nutritional value and quality.
Basic steps include:
* Immediate Cooling Fish should be stored in a low-temperature environment like ice or refrigerated seawater to slow microbial growth and enzyme activity.
* Preprocessing Operations such as inspection, washing, sorting, grading, and butchering prepare the fish for final processing. Butchering involves removing nonedible parts.
* Final Processing Basic procedures like heating, freezing, controlling water activity, and irradiation extend shelf life by inhibiting spoilage.
* Curing Reduces water activity by adding chemicals like salt, sugar, or acids. Methods include dry salting and pickle-curing.
* Smoking Combines drying and adding chemicals from smoke, preserving and flavoring the fish.1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How does fish processing help keep fish safe to eat?
Fish processing helps keep fish safe to eat through methods that prevent spoilage and degradation. Immediate cooling after harvesting slows microorganism growth and enzyme activity, which are more rapid in fish than in land animals.
Other processing techniques, such as freezing, drying, heating, curing, and irradiating, extend shelf life by hindering spoilage mechanisms. Curing, for example, reduces water activity using salt, sugars, or acids, which inhibits microbial growth and slows detrimental chemical reactions. Washing, trimming fat, and removing skin also helps to reduce the intake of toxic substances.
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What are some different methods of preserving processed fish?
Fish processing uses methods like heating, freezing, irradiation, or controlling water activity to extend shelf life by preventing spoilage and degradation.
Methods of preservation:
* Canning Fish is sealed in containers and heated to high temperatures, which sterilizes the fish.
* Curing Reduces water activity by adding salt, sugar, or acids. Methods include dry salting, where fish is buried in salt to reduce water content, and pickle-curing, where fish is preserved in airtight barrels using a strong salt solution.
* Smoking Combines drying and adding chemicals from the smoke, which adds flavor and aids preservation. Cold-smoking doesn't cook the fish, while hot-smoking does.
* Freezing Cooling and holding, rapid freezing, and cold storage are the three steps for freezing fish. Rapid freezing is key to maintaining flavor and quality.1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How has modern technology changed fish processing over time?
Modern technology has significantly revolutionized fish processing, enhancing efficiency and preservation. Freezing, an essential method, maintains flavor and quality by rapidly reducing temperatures to halt biochemical reactions. This prevents enzymatic degradation, texture changes, and dehydration, which can compromise the fish's structural integrity.
Mechanization, which started in the late 19th century, has led to larger catches using bigger fishing gear. Post-World War II, synthetic fibers replaced natural ones in net making, and the introduction of power blocks and power-driven drums further mechanized hauling. Computer analyses and mathematical models now help fisheries scientists predict optimal yields, though overexploitation and pollution remain major concerns.
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fish processing, preparation of seafood and freshwater fish for human consumption.
The word fish is commonly used to describe all forms of edible finfish, mollusks (e.g., clams and oysters), and crustaceans (e.g., crabs and lobsters) that inhabit an aquatic environment. Fish from the marine and freshwater bodies of the world have been a major source of food for humankind since before recorded history. Harvesting wild fish from fresh and marine waters and raising cultured fish in ponds were practices of ancient Egyptians, Greeks, and other Mediterranean peoples. Rudimentary processing techniques such as sun-drying, salting, and smoking were used by these ancient groups to stabilize the fish supply. Modern methods of processing and preservation have encouraged the consumption of many species of fish that are popular throughout the world.
Characteristics of fish
Structure of skeletal muscles
The majority of edible fish products are derived from the skeletal muscles (flesh), which represent more than 50 percent of the total body mass of these animals. The skeletal muscles of fish differ from those of mammals and birds in that they are largely composed of stacks of short bundles of muscle fibres called myomeres. The myomeres are separated by thin horizontal (myosepta) and vertical (myocommata) layers of connective tissue. The unique structure and thin connective tissue sheaths of fish muscle give the meat its characteristic soft, flaky texture.
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The skeletal muscles of fish are composed mostly of white, fast-twitch fibres. The high percentage of white fibres allows fish to swim with sudden, rapid movements and gives the meat its white colour. These fibres primarily metabolize glucose, a simple sugar released from muscle glycogen stores, for energy production through anaerobic (i.e., in the absence of oxygen) glycolysis. Therefore, white fibres contain relatively little myoglobin, the oxygen-binding protein that provides the red colour of muscles in other animals.
Nutrient composition
The composition of fish may vary considerably—especially in their fat content—during certain growth periods and annual spawning or migration periods. In addition, the composition of fish bred in captivity (i.e., aquaculture fish) may vary according to their artificial diet. The table shows the nutrient composition of several types of fish.
| species | energy (kcal) | water (g) | protein (g) | fat (g) | cholesterol (mg) | calcium (mg) | iron (mg) | riboflavin (mg) | niacin (mg) |
|---|---|---|---|---|---|---|---|---|---|
| Source: U.S. Department of Agriculture, Composition of Foods, Agriculture Handbook no. 8–11. | |||||||||
| catfish, channel (farmed) | 135 | 75.38 | 15.55 | 7.59 | 47 | 9 | 0.50 | 0.075 | 2.304 |
| cod, Atlantic | 82 | 81.22 | 17.81 | 0.67 | 43 | 16 | 0.38 | 0.065 | 2.063 |
| grouper, mixed species | 92 | 79.22 | 19.38 | 1.02 | 37 | 27 | 0.89 | 0.005 | 0.313 |
| haddock | 87 | 79.92 | 18.91 | 0.72 | 57 | 33 | 1.05 | 0.037 | 3.803 |
| halibut, Atlantic or Pacific | 110 | 77.92 | 20.81 | 2.29 | 32 | 47 | 0.84 | 0.075 | 5.848 |
| herring, Atlantic | 158 | 72.05 | 17.96 | 9.04 | 60 | 57 | 1.10 | 0.233 | 3.217 |
| mackerel, Atlantic | 205 | 63.55 | 18.60 | 13.89 | 70 | 12 | 1.63 | 0.312 | 9.080 |
| salmon, Atlantic | 142 | 68.50 | 19.84 | 6.34 | 55 | 12 | 0.80 | 0.380 | 7.860 |
| salmon, pink | 116 | 76.35 | 19.94 | 3.45 | 52 | — | 0.77 | — | — |
| trout, rainbow (wild) | 119 | 71.87 | 20.48 | 3.46 | 59 | 67 | 0.70 | 0.105 | 5.384 |
| tuna, bluefin | 144 | 68.09 | 23.33 | 4.90 | 38 | — | 1.02 | 0.251 | 8.654 |
| clam, mixed species | 74 | 81.82 | 12.77 | 0.97 | 34 | 46 | 13.98 | 0.213 | 1.765 |
| crab, blue | 87 | 79.02 | 18.06 | 1.08 | 78 | 89 | 0.74 | — | — |
| lobster, northern | 90 | 76.76 | 18.80 | 0.90 | 95 | — | — | 0.048 | 1.455 |
| oyster, Pacific | 81 | 82.06 | 9.45 | 2.30 | — | 8 | 5.11 | 0.233 | 2.010 |
| scallop, mixed species | 88 | 78.57 | 16.78 | 0.76 | 33 | 24 | 0.29 | 0.065 | 1.150 |
| shrimp, mixed species | 106 | 75.86 | 20.31 | 1.73 | 152 | 52 | 2.41 | 0.034 | 2.552 |
Proteins
Fish are an excellent source of high-quality protein. Mollusks are generally lower in protein compared with finfish and crustaceans because of their high water content. The proteins found in fish are essentially the same as those found in the meat derived from other animals—that is, the sarcoplasmic proteins (e.g., enzymes and myoglobin), the contractile or myofibrillar proteins (e.g., actin and myosin), and the connective tissue proteins (i.e., collagen).