1. The key points of sensory identification of aquatic products and aquatic products
Sensory identification of aquatic products and their quality is mainly based on the body surface morphology, freshness, color, smell, meat elasticity and cleanliness and other sensory indicators for comprehensive evaluation. For aquatic products, the first is to observe how their liveliness and whether they have a certain vitality; the second is to look at the integrity of the appearance of the body, pay attention to the presence of scars, detached claws, separation of flesh and meat, etc.; again observe the body The degree of cleanliness of the table is the presence or absence of filth and impurities. Then it is to look at its color, smell its smell, and taste its taste if necessary. In summary, the sensory evaluation was performed again. For aquatic product education, the sensory identification is mainly the appearance, color, smell and taste. Whether or not it has the typical normal smell and flavor of the product is of great significance in making a correct judgment.
2, identify the quality of fresh fish
In the sensory identification of fish, first observe their eyes and blemishes, then check their body and scales, and at the same time, use a clean absorbent paper to absorb the mucus on the scales to observe and smell, to identify the quality of mucus. If necessary, use a bamboo stick to pierce the fish, smell it immediately after pulling it out, or cut a small piece of fish and measure the smell and taste of the fish soup after boiling.
(1) Eyeball identification
Fresh fish - The eyeballs are full and the cornea is transparent and clear and elastic.
Secondary fish - the eyeball is not prominent, the cornea is wrinkled, slightly turbid, and sometimes red blood inside the spill.
Corrupt fish - The eyeball collapses or dries, and the cornea shrinks or breaks.
(2) Identification of fish gills
Fresh fish - The silk is clear and bright red. The mucus is transparent. It has salty smell of sea fish or earthy smell of freshwater fish.
The second fish - dark reddish gray or gray purple, mild mucus odor, bad smell.
Corrupt fish - brownish or grayish white, dirty mucus with an unpleasant rancid odor.
(3) Body Surface Identification
Fresh fish - transparent mucus, scales shiny and closely attached to the fish body, not easy to fall off (except wolfberry, large yellow croaker, small yellow croaker).
Sub-fresh fish - more mucous opacity, scales poor gloss and easier to fall off, mucus sticky and cloudy.
Corrupt fish - body surface dull, with dirty mucus on the surface, scales and fish skin depleted, with rancid odor.
(4) muscle identification
Fresh fish - the muscles are firm and elastic, the depression disappears immediately after the finger pressure, there is no odor, and the muscle section is glossy.
Fresh fish - muscles are slightly loose, the depression disappears slowly after acupressure, slight odor, and shiny muscle section.
Corrupt fish - loose muscles, easy to separate from fish bones, depression formed by finger pressure can not be restored or fingers can pierce the fish.
(5) Identification of abdominal appearance
Fresh fish - normal abdomen, no swelling, white anal hole, depression.
Fresh fish - abdominal swelling is not obvious, slightly protruding anus.
Corrupt fish - The abdomen swells, softens, or ruptures, with dark gray or light green spots on the surface, and the anus protruding or broken.
3, identify the quality of frozen fish
After the fresh fish is frozen at a low temperature of -23°C, the fish body becomes hard and its quality is not as easy to distinguish as fresh fish. The identification of frozen fish should pay attention to the following aspects:
(1) Body surface: good quality frozen fish, bright color and fresh fish-like bright, clean surface, anal tightening. Poor quality frozen fish, dark dull surface, protruding anus.
(2) Fish eyes: Frozen fish with good quality, full eyeballs protruding, cornea transparent, clean without dirt. Poor quality frozen fish, the eyeball is flat or slightly depressed, and the cornea is turbid and white.
(3) Organization: Good quality frozen fish, complete body shape, with a knife to open the inspection, the meat is not strong sting, there is no red line at the spine, the gallbladder is not broken. Poor quality frozen fish, incomplete in shape, cut open with a knife, loose flesh, stabbing phenomenon, gallbladder rupture.
4, identify the quality of salted fish
(1) Color identification
Good quality salted fish - fresh and shiny.
Substandard salted fish - the color is not bright or dark talk.
Inferior salty fish - yellow or red on body surface.
(2) Body surface identification
Good quality salted fish - complete body surface, no broken belly and flesh and meat separation, flat shape, no residual scales, no dirt.
Sub-alkali salted fish - The fish is basically intact, but there may be a small amount of red or mild deterioration, a small amount of residual scales or dirt.
Inferior salted fish - incomplete body surface, separated flesh, debris and dirt, there are mildew phenomenon.
(3) muscle identification
Good quality salted fish - succulent and firm, elastic.
Substandard salted fish - slightly softer and less elastic.
Inferior salted fish - loose meat easily scattered.
(4) Odor identification
Good quality salted fish - with the unique flavor of salted fish, moderate salty.
Substandard salted fish - can have mild odor.
Inferior salted fish - has a significant rancid odor.
5, identify the quality of dried fish
(1) Color identification
Good quality dry fish - clean and shiny appearance, no salt on the surface, white or light fish
Sub-quality fish - poor appearance gloss, darker color.
Inferior dry fish - dull, dull, dull, reddish or grayish, yellow-brown, yellowish.
(2) Odor identification
Good quality dry fish - with the normal flavor of dried fish.
Substance dried fish - may have a slight odor.
Inferior dried fish - with sour, fatty acid or corrupt odor.
(3) Identification of organizational status
Good quality dried fish - complete fish, dry feet, good flesh toughness, smooth, crack-free, broken and incomplete at the cutting edge.
Sub-quality dry fish - the appearance of the fish is basically perfect, but the meat is less tough.
Inferior dry fish - loose meat, cracked, broken or incomplete, high moisture content.
6, identify the quality of yellow croaker
The quality of yellow croaker is generally distinguished from the fish's body surface, fish eyes, fish gills, muscles, and mucous cavity.
(1) Body surface: Fresh and well-rounded yellow croakers are golden yellow and shiny on the body surface. The scales are complete and not easy to fall off. Fresh yellow croakers are pale yellow or white, with poor luster, incomplete scales and easy to fall off.
(2) Fish gizzards: fresh large yellow croakers, bright red or purple red, small yellow fish mostly dark red or purple. Odorless or fishy odor, clear silk. Fresh yellow croakers are dark red, dark purple or brownish yellow and grayish red. They have rancid odors, but they have no foul odor and sticky silk.
(3) Fish eyes: fresh and well-rounded yellow croakers, full of convex eyes, and transparent cornea. Fresh yellow croaker, flat or slightly depressed eyeball, slightly cloudy cornea.
(4) Muscles: Fresh and well-rounded yellow croakers are firm and elastic. Fresh yellow croakers have loose muscles and poor elasticity. If the belly is soft or crooked, it is a metamorphic yellow croaker.
(5) Liquid cavity: Fresh and good yellow fish, the mucus is bright red. Fresh yellow fish, mucus cavity pale red.
7, identify the quality of the fish
The quality of striped fish can be identified from the following aspects:
(1) Body surface: The quality of octopus is good, the body surface is shiny, the whole body is full scale, the scales are not easy to fall off, the wings are all full, and there is no phenomenon of breaking belly and breaking the head. Poor quality octopus, poor surface gloss, scales easily fall off, the body only a few silver phosphorus, the fish body becomes fragrant gray, there are broken belly and broken phenomenon.
(2) Fish eye: Good quality octopus, full eyeball, and transparent cornea. Poor quality of octopus, the eye slightly collapsed, the cornea was slightly turbid.
(3) muscles: good quality octopus, thick muscles, elastic. Poor quality octopus, weak muscles, poor flexibility.
(4) Quality: Good quality octopus, each weighing 0.5 kg or more. Poor quality octopus, each weighing about 0.25 kg.
8, identify the quality of carp
The squid is a saltwater fish. It is also known as white bream, flat fish, mirror fish, car fish, and silver bream. The weight of the carp can be observed from the body surface, fish gills, fish eyes, muscles and other parts.
(1) Body surface: The quality of the carp is good, the scales are close to the fish body, and the fish body is firm and shiny. Poor quality squid, scales are easy to fall off, fish body is less shiny or dull.
(2) Fish gizzards: The gills are of good quality, the gills cover are opened, and the spittoons are purplish red or red with clear and bright quality. The gills are dark purple or grayish red, with turbidity and slight odor.
(3) Fish eyes: Good quality carp, full eyes, and transparent cornea. Poor quality squid, eyeball depression, cornea more sticky.
(4) Muscles: The quality of the carp is good, the meat is dense, and the hand touch elasticity is good. Poor quality squid, loose meat, poor hand touch flexibility.
(5) Gender: The female is large and fleshy. The male body is small and the meat is thin.
9, identify the quality of carp
The squid is also known as the phoenix, the scorpion, the tail fish, and the croaker. It is a kind of Jianghai migratory fish that grows in the ocean and reproduces fresh water, especially in the Yangtze River. Carp is characterized by a narrow and flat body, with anal fins and caudal fins connected together. There are five beards on the pectoral fins. The tips are small, and the color is silver and white, resembling a sharp knife. Squid is a rare fish. Its meat is tender, soft and delicious.
The quality of carp can be checked from the body surface, fish gills, fish eyes, and smell.
(1) Body surface: Good quality carp, scales close to the fish, shiny. Poor quality carp, scales loose, easy to fall off, poor surface gloss.
(2) Fish gizzards: The gills are of good quality, and the gill cover is opened. The gill filaments are yellow and clear and bright. Poor quality squid, cocoon pale yellow, and adhesion phenomenon.
(3) Fish eyes: Good quality carp, full eyeball, clear and transparent. Poor quality carp, with flat or slightly sunken eyes, slightly turbid.
(4) Odor: Good quality carp, no smell. Poor quality squid smells.
10, identify the quality of carp
The squid is a saltwater fish. It is also known as squid, blue-and-white mackerel, oil tube fish, squid, and flower pots. The quality of carp can be checked from the body surface, fish gills, fish eyes, muscles and other parts.
(1) Body surface: Good quality carp, shiny, and clear texture. Poor quality carp, poor surface gloss, visible texture.
(2) Fish carp: The quality carp is good, the carcass is dark red, no peculiar smell, there is a transparent and uniform mucus covered, clear silk. Poor quality of the fish, the body was dark purple or grayish brown, slightly odor, silk adhesion.
(3) Fish eyes: Adhered carp, full eyeballs, and transparent cornea. Poor quality squid, flat or depressed eyeballs, cornea sticky turbidity, and some red eyes.
(4) Muscles: Good quality squid, firm meat, and elastic hands. Poor quality carp, loose flesh, poor hand touch flexibility, if the belly soft yellow, belly broken, paste mouth, etc., indicating that the fish body is poisonous, people eat swollen body. ,
11, identify the quality of carp
Carp is one of the most important economic fishes in the world. There are catfish production in the Yellow Sea and Bohai Sea in China. The quality of carp can be identified from the body surface, fish gills, fish eyes, muscles, anus and other parts.
(1) Body surface: The quality of the squid is good. The back is black and shiny. Poor quality carp, poor luster, back dark black.
(2) Fish gills: Good quality trout, bright red color, and clear silk. Poor quality fish, dark red or dark purple, sticky silk, have stench.
(3) Fish eye: The quality of the carp is good, the eyeball is full and convex, and the cornea is transparent. In poor quality salmon, the eyeball is flat or slightly depressed, and the cornea is cloudy.
(4) Muscles; good fish are of good quality and have elastic hands. Poor fish, loose flesh, poor hand touch flexibility.
(5) Anus: Good quality fish, the anus is in a tight state. Poor quality, the anus protrudes outward.
12, identify the quality of carp
The squid, also known as naked quail, is produced in Qinghai Lake and is a valuable fish with high economic value. Quality can be differentiated from fish gills, fish eyes, muscles and abdomen.
(1) Fish gizzards: The trout with good quality, bright red silk, and clear mucus have the inherent odor of salmon. Poor quality squid, gray silk red, slightly muddy mucus, smell a little smelly.
(2) Fish eyes; good quality carp, full eyeball protrusion, corneal transparency. Poor quality carp, the eye is convex or flat, and the cornea is slightly turbid.
(3) Muscle: Good quality squid, firm meat, good touch of hand touch. Poor quality carp, loose meat, poor hand touch flexibility, there is a stabbing phenomenon.
(4) Abdomen: The quality is good, the abdomen does not swell, and the anus tightens. Poor quality squid, abdomen swells or breaks belly, bowel overflows, and the anus protrudes.
13, identify the quality of fish
Pool fish, also known as stick fish. Because of the high yield and good meat quality, it is popular with consumers. Its quality can be identified from the body surface, fish gills, fish eyes, muscles and other parts.
(1) Body surface: Good quality fish, bright shiny, scales intact, not easy to fall off. Poor quality pond fish, poor surface gloss, phosphorus film is incomplete, easy to fall off.
(2) Fish gills: Good quality pond fish, bright red silk, clear. Poor quality pond fish, Bosch color red or purple, silk sticky, no smell or slight foul smell.
(3) Fish-eye: Fish of good quality, full and protruding eyes, and transparent cornea. Poor quality fish, flat or slightly depressed eyeballs, slightly cloudy cornea.
(4) muscles: good quality fish, solid meat, good elasticity. Poor quality fish, loose flesh, poor flexibility.
14, identify the quality of shrimp
The quality of shrimp is distinguished from the aspects of color, body surface, muscle, smell and so on.
(1) Color: Good quality prawns, normal color, yolk show a natural luster in different maturation periods, poor quality of the prawns color red, yolk shows a different dark gray.
(2) Body surface: Good quality prawns, shrimp bodies are clean and intact, there is no shedding of shells and tails, shrimp tails are not discolored or have slight discoloration, poor quality shrimps, incomplete shrimp bodies, and body dark spots The shells and tails fell off, and the tails were discolored.
(3) muscle: good shrimp, muscle tissue is firm, hand touch elasticity, poor quality shrimp, muscle tissue is loose, poor hand touch flexibility.
(4) Odor: Good quality prawns, smelling normal, no peculiar smell, poor quality prawns, smelling abnormal smells, and generally smelly smells.
15, identify the quality of shrimp
Green shrimp is also known as shrimp, giant shrimp. It belongs to freshwater prawn and it is rich before and after the Dragon Boat Festival. The characteristics of the shrimp are: the head has whiskers, the chest has claws, the two eyes are prominent, the tail is shaped again and again, the body surface is blue, the meat is crisp, and the taste is delicious.
The superiority and inferiority of the quality of the shrimp can be distinguished from the surface color of the shrimp, the degree of head body connection and the muscle condition.
(1) Body color: good quality shrimp, greenish gray, clear and transparent shell. Poor quality shrimp, gray color, poor transparency of the shell.
(2) Degree of head body connection: The shrimp with good quality has a tight head connection and is not easy to fall off. In poor quality shrimp, the head is not tightly connected and is easily detached.
(3) muscle: good quality shrimp, white color, close meat, tail section flexion strong. Poor quality of the shrimp has poor color and whiteness, slightly fleshy texture, and somewhat inferior extension and flexion of the tail section.
16, how to identify the quality of shrimp oil?
(1) Good-quality shrimp oil - Pure shrimp oil is not boiled, the color is clear and not mixed, and the oil is thick. The smell is fresh and fragrant. Salty, light and clean.
(2) Subprime shrimp oil - the color is clear and not mixed, but the oil is relatively thin, and the smell is fresh but there is no rich fragrance. Slightly different salty taste, clean and sanitary.
(3) Inferior shrimp oil - the color is dark and turbid, and the oil is thin as water. The umami taste is not strong and there is no fragrance. The taste is salty and astringent.
17, identify the quality of shrimp paste
(1) Good quality shrimp paste - pink in color, shiny and savory. The paste was thick paste. No impurities, hygienic and clean.
(2) Inferior Shrimp Paste - It is reddish, dull, and smelly. The sauce is thin and not sticky. Mixed with impurities, unsanitary.
18, identify the quality of crab
(1) Body surface identification
Fresh sea crab - bright body surface, back shell texture is clear and shiny. The color of the abdomen's carapace and central sulcus is white and shiny, and no upper part of the umbilicus has stomach marks.
Sub-fresh crabs - surface color dim, poor gloss, abdominal umbilical can appear a slight "blot", ventral central groove darkening.
Corrupted crabs - dark and dull carcasses on the body surface and in the abdomen. Grayish brown spots or plaques in the mid-stomach of the abdomen, or yellow granular rolling substances can be seen.
(2) Identification of Crabs
Fresh sea crab - clear silk, white or slightly brownish.
Sub-fresh crabs - silk is still clear, dark color, no smell.
Corrupted sea crabs - Filament is blurry, dark brown or dark gray.
(3) Identification of limbs and freshness
Fresh Sea Crabs - Live crabs that have just been caught have limbs that are tightly connected and do not sag or droop when the crabs are raised. Live crabs are alert and quick and powerful.
Sub-fresh crabs - live crabs with markedly reduced vitality, are unresponsive, slow and weak. The degree of limb attachment was poor. When the crabs were lifted, the crabs' feet were slightly sagging or distorted.
Corrupted sea crabs - dead crabs that have no life, can no longer be active. The degree of limb connection is very poor. When the crab body is lifted, the crab's feet are perpendicular to the crab's back, and the foot is incomplete.
19, identify the quality of crab
(1) Fresh crabs - Live crabs with strong activity ability. They are sensitive and able to crawl on the palms and feel heavy and heavy.
(2) The fresh crabs - legs and legs, can not turn over when put up, but the crab can move slightly. When you are heavy, you can feel it is good enough.
(3) Inferior crabs - dead crabs that cannot move at all. When weighed, it gives people a sense of emptiness and frivolity.
20. Differentiate the quality of river otters
Fresh river oysters, the clam shell cover is tightly closed, the hand is not easy to open, smell the smell of smelly smell, open the clam shell with a knife, the internal color is bright, the meat is white. If the clam shell does not close tightly, open it by hand, there is a stench of stench, dark gray flesh, it is dead river clams, bacteria are the most prolific, the meat is easy to decompose and produce putrefaction, this clam can not be eaten.
21, identify the quality of oysters
Oyster, also known as jellyfish, is a shellfish mollusk consisting of two left and right shells. The right shell is called the upper shell, the left shell is called the lower shell, and the left shell is attached to the rocks, bamboo, and tiles. The shell moves up and down, feeding, breathing, breeding, and defending the enemy.
Oyster is a delicious shellfish food. Fresh and good quality oysters, full or slightly soft, carious, milky white, body fluids clear, white or light gray, with the inherent smell of oysters. Poor quality oysters, dark in color, bodily fluids are turbid, have offensive odors and are not edible.
Oyster harvest time is generally the most fat winter and spring in the two seasons, the northern production of oysters is small, Guangdong security county production is big.
22, identify the quality of dumplings
The coriander, also known as corrugated, is a special product of our country. Due to the tenderness and deliciousness of the meat, it is considered as a delicacy.
Fresh scorpions, bright shell, two shells tightly closed, easy to open, smell no smell. If the skin of the shell falls off, the shell becomes black and the two shells open, and the smell is offensive, indicating that it is dead and cannot be eaten. At present, some hawkers use shellfish that have been opened to death and use large amounts of mud to make them mistaken for live pigtails.
23, identify the quality of calyx
Fresh flower pods, shells with inherent color, usually open mouth slightly, frightened when two shells close tightly, axe foot and contact tube flexible, with inherent odor. If two shells are open, the feet and the contact tube do not have the ability to stretch, and if they smell strange, they cannot eat it.
24, identify the quality of boiled shellfish
(1) fresh shellfish - normal and shiny color, no smell, hand feel smooth, good elasticity.
Not fresh shellfish - the color is reduced or dull, there is sour, feel sticky, poor flexibility.
(2) Fresh erythrobis - dark yellowish brown or light yellowish brown, shiny, with good elasticity.
Not fresh erythras - grayish yellow or light green, dull, inelastic.
(3) fresh conch meat - milky yellow or light yellow, shiny, elastic, local purple rose spots.
Not fresh conch meat - white or gray, dull, inelastic.
25, identify the quality of the foot
(1) Color identification
Fresh foot - with the inherent fresh color of this species, pigment spots are clear, the body surface is shiny, mucus is more and clear.
Metamorphic foot - pigment spots are blurred, and they appear as a piece of red, with mucus on the surface.
(2) muscle identification
Fresh feet - body meat soft and smooth, elastic.
Metamorphic foot - body fat stiff astringent or excessively soft, inelastic.
(3) Identification of eyeballs and odors
Fresh feet - eyeball full and prominent, shiny, body meat without abnormal smell
Metamorphic foot - eyeball collapsed and dull, with stench.
26, identify squid and squid
(1) How to identify squid and squid by pressing and shape
Press hard on the middle of the corpus callosum with your fingers. If there is a hard feeling, it is a squid fish. If it is soft, it is a carp. Because the squid has a hard, cuttlefish bone like a boat, and the eel has only a leaf-like transparent film that crosses the body, it feels different. In addition, squid are generally slender body shape, the end was a long rhombus-shaped, meat fins are separated on both sides of the corpus callosum, when viewed upside, much like a "marine head", and squid shape slightly shoulder width, and squid The other features are also different.
(2) Quality identification of carp
The common squid on the market has two kinds of elongated and oval. The eel's shape is elongated, the squid-shaped dry product is oval, and it is educated in terms of quality. The elongate shape is superior to the oval shape.
Good quality carp body is thick and solid, body meat is dry, slightly translucent red, no mold. The tender carp is yellowish in color, transparent and thin. The old squid has a purple color and a large body.
27, identify the quality of jellyfish head
The quality of jellyfish heads is divided into two grades.
(1) First-grade products: Complete dried meat, light red color, rich light, crunchy texture, no silt, broken bar and inclusions, no smell.
(2) Second-grade products: The dried meat is complete, the color is red, the light is poor, there is no sediment, but there are a few broken bars and inclusions, and there is no smell.
Before eating jellyfish, check it carefully to avoid causing intestinal diseases. The inspection method is to use two fingers to pick up the jellyfish head, if it is easy to break, the meat is crispy, and the color is purple and black, indicating that it is broken and cannot be eaten.
28, identify the quality of jellyfish
(1) Color identification
Good jellyfish skin - white, milky or light yellow, wet and shiny surface, no obvious red spots.
Sub-seagrass - gray or dark brown, poor surface gloss.
Inferior jellyfish skin - dark gray or blackish on the surface.
(2) Fragile identification
Good quality jellyfish - crispy and resilient, buzzing when chewing.
The sub-quality jellyfish - poor crispness, no toughness.
Bad jellyfish - crisp texture, easy to tear, no brittleness and toughness.
(3) Thickness Identification
Good quality jellyfish - uniform thickness throughout.
Secondary jellyfish skin - uneven thickness.
Inferior jellyfish skin - uneven thickness.
(4) Shape identification
Good quality jellyfish skin - natural round, with no holes in the middle, edges do not break.
Secondary jellyfish skin - incomplete shape, broken phenomenon.
Inferior jellyfish skin - incomplete shape, easy to break.
29, identify fish with illness
Diseased fish can be identified from the following aspects:
(a) The body surface of fish
Generally suffering from sick fish, the muscles on both sides of the body, the base of the fins, especially the base of the anal fins are all congested. According to the different parts of the fish body, there are several kinds of common diseases:
(1) Hemorrhagic disease: The slightly muscular condition of the disease is somewhat straightened: The body muscles with a heavy illness are dark red.
(2) erythroderma disease, the fish's body surface has partial congestion, inflammation, scales off phenomenon.
(3) Print disease: Round ovoid erythema appears on the tail or on both sides of the abdomen. The diseased muscle rots into small pits, showing bones and internal organs.
(4) Fish wind disease: There are pale green spots on the body surface of the fish. The body of the bugs is crawling.
(5) Saprolegnia: on both sides of the fish body, up and down the abdomen and back, etc., there are cotton-like white long hairs.
(6) Trichodiasis: Frigs and fingerlings do irregular scampering along the edge of the pond or on the surface of the water, and there are red spots on the head.
(7) Enteritis: The anus of the fish is red and swollen, with inflammation and congestion.
(8) Ophthalmopathy: The prominent fish eye is caused by high levels of organic acid or ammonia in the water and high nitrogen content.
(B) Silk color
The silk is white, the tip cartilage is exposed, the ends of the silk are uneven, and the mucus is more. The cocoon silk is arranged irregularly with purple-red dots, and the white silkworm body at the end of the cocoon wire is Chinese juvenile aphid disease. The silk surface is light white with bumpy spots. It is a trichoderma or a pseudoflagellate disease.
(c) Intestinal color
Peel the fish off to observe the intestine. If the intestine is completely or partially reddish, the thickness is not uniform, and the meat has beige mucus, it is bowel disease. If the intestine of the herring is white, the front end is swollen, and there are many white cotton-like nodules on the inner wall of the intestine, it is coccidiosis.
30. Identify poisoned fish
In farmers' markets, fish that are poisoned by pesticides are often sold. When buying, pay special attention. Poisonous fish should be identified from the following aspects:
(1) Fish mouth: After the normal fish dies, the closed mouth can naturally open. Poisonous fish, fish mouth closed, not easy to pull naturally.
(2) Fish gizzards: Fresh fish that normally die, and its pod color is bright red or reddish. Poisonous fish, purple or brown red.
(3) fins: Normal dead fish with membrane fins close to the abdomen. Poisoned fish, pelvic fins open and hard.
(4) Odor: Normal dead fish, there is a fish smell, no other smell. Poisoned fish can smell a bit of pesticide from fish bladders, but it does not include odorless pesticides.
31. Identify contaminated fish
Because rivers and lakes are affected by the discharge of industrial waste water, they cause fish to be contaminated and die, and these contaminated fish are often sold on the market. The identification of contaminated fish has the following aspects:
(1) posture: contaminated fish, often deformed, such as the head and tail small, or head small tail, abdomen made soft, spine bent, fish scale color yellow, red or blue.
(2) Fish eyes: Contaminated fish. The eyeballs are cloudy and dull, and some of the eyes protrude outward.
(3) Fish gills: Contaminated fish gills have a dull colour and usually have a whitening majority.
(4) Odor; Contaminated fish, generally smells of ammonia, kerosene, hydrogen sulfide, etc., lack fishy smell.
32. What part of puffer fish contains toxins?
Puffer fish toxins are mainly found in the ovary and liver, followed by kidneys, blood, eyes, fish gills, and fish skin. Some puffer fish also contain toxins in their meat. During the winter and spring, ovarian toxins are the most toxic. If people eat a piece of fish like a finger, they will be poisoned.
33. Which part of the carp contains toxins?
The squid is also known as squid and mackerel. The blood of this fish is black. After the cut of the fish's back, there is a blood line. The blood line is poisonous. If the fish is washed, the blood line will not be removed. Cooking and eating with the fish will cause the body to produce Allergy phenomenon, if the fish's abdomen is soft yellow, broken belly, paste mouth, etc., indicating that the fish has deteriorated and spoiled, if people eat this fish, will make the body swollen.
34. Which parts of the carp are toxins?
The squid is also known as Blue Point Horse Hinge, Blue Point Stork, and Swallow Fish. Its quality is characterized by less spiny meat, garlic-shaped flesh, more tender. However, the liver of this fish contains toxic substances and cannot be eaten. Therefore, the fish liver must be removed when cleaning the fish.
35. Which part of the pond fish has toxins
The fish is also known as blue round, stick fish, barb fish, pool fish and so on. This fish should be fresh and safe. If released for a long period of time, histidine in the fish will decompose rapidly and produce toxic ammonia. If people eat this fish, food poisoning will occur.
36, which part of the carp contains toxins
The squid is also known as squid, squid, and beard. It is a kind of freshwater wild fish, which is distributed in Heilongjiang River, Yellow River, Yangtze River and Pearl River Basin in China. It is a kind of fish with rich nutrition and tasty meat. However, when cleaning this fish, be sure to remove the eggs, because it is toxic and inedible.
37. Which part of the carp contains toxins?
The squid is also known as white cricket, scorpion, bitter chain and so on. It is a common freshwater fish, which is common throughout the year in the farmers' market in the Mainland. It is a popular and inexpensive fish. When people wash this fish, they need to remove the fish liver because it contains Poisonous to prevent food poisoning.
38. Which part of the carp is poisoned?
Squid is produced in Qinghai Lake. The viscera and eyes of this fish are poisonous. When cleaning fish, the internal organs and eyes must be removed to prevent food poisoning.
39. Which part of the river turtle contains toxins?
The river clams are also known as cockroaches, eel, and white cockroaches. The fish's serum contains toxins, wound fingers, do not come into contact with the river blood, in order to prevent wound inflammation, suppuration.
40. Why did Huang Fei eat food?
Astragalus also known as carp, long fish and so on. In the private sector, there is a saying that "Summer Yellow Ginseng Race Ginseng" is said to be popular today. However, one thing to note is that squid can only eat fresh, slaughter is cooking, and should not eat dead stingray. Because the histidine contained in the body will quickly turn into toxic histamine after the death of the stingray, people will cause food poisoning after eating. The blood serum of Astragalus contains toxins. If there are wounds on the fingers of the people, once they come into contact with the blood of the fish, the wounds will become inflamed and purulent.
41. Why can't eat dead turtle?
The soft-shelled turtle is also known as the group of fish. Due to its tender meat, rich flavour and rich nutrition, the soft-shelled turtle is considered to be a tonic. However, dead turtles cannot eat. Since soft-shelled turtles contain more histidine, histidine is an important ingredient that has a special umami taste, and it can produce histamine after decomposition. Histamine is a strong straight tube expander, which can cause the release of a series of allergic substances. When the concentration is too high, it can cause symptoms such as prostration and shock. After the death of the soft-shelled turtle can be self-decomposition to produce ammonia, people eat dead turtles, it will cause food poisoning.
42. Sensory identification of fresh aquatic products after boiling experiments
For aquatic products that are slightly less or have a slight odor, when the sensory identification method is used to determine the freshness of the product, it is possible to smell the odor and taste the taste after the brew test, and identify with the observation of the soup. When boiling test, the sample is generally not more than half a kilogram, and the amount of water discharge is appropriate to just immerse the sample. First, the water in the container is boiled, and then the sample of the deceased person and the lid of the container are heated. When the bottle is boiled again, the heat source is removed, and then the lid is opened for identification.
(1) Odor identification
The scent of fresh products - with the inherent flavor of this species.
The odor of deteriorating products - there is a stench or ammonia smell.
(2) Identification of taste
The taste of fresh products - This product has a delicious taste that is inherent in this product. The texture of the meat is elastic.
The taste of the deteriorating product - no umami, fleshy hair, ammonia odor.
(3) Soup Identification
Fresh soup - soup clear, with the color of this type of pigment, no minced meat in the soup.
Deteriorated soup - turbid soup, fleshy spoilage suspended in the soup.
43. Rapid test of freshness of aquatic products
(1) Determination of pH
Operation: The same pH value as in the meat freshness test.
Identification: fresh fish - pH 6.5 ~ 6.8.
Fresh fish - The pH is 6.9-7.0.
Metamorphic fish - the pH is above 7.1.
(2) Hydrogen Sulfide Measurement Operation: Weigh 20 grams of sample fish into a small jar, add 40 ml of 10% sulfuric acid solution, and place a square or round filter paper larger than the bottle mouth in the middle of the filter paper block. Drop 1 to 2 drops of 10% lead acetate alkaline solution, and then place the drop with one side down on the bottle mouth and use a rubber band. After 15 minutes, remove the filter paper and observe the color change.
Identification:
Fresh fish - Lead acetate alkaline solution, no change in color, negative reaction (-).
Fresh fish - Appears slightly brown or brown near the edge of the sputum, as a suspected reaction () or a weak positive reaction (+).
Corrupt fish - all drip sites are brown, darker at the border, positive reaction (+ +), or dark brown, strong positive reaction (+++).
(3) Determination of ammonia
Operation: Take a large piece of fish meat, hung on a glass rod with a rubber stopper attached to the other end with a hook, and use a pipette to draw Aibeier's test solution (take 15% of hydrochloric acid with a specific gravity of 1.12 and 1 part of anhydrous ether, 96%). Mix 2 ml of 3% alcohol and inject it into the test tube. After slightly shaking, place the glass rod with rubber stopper into the test tube (be careful not to touch the wall) until the sample is 1 to 2 feet away from the liquid surface. At a centimeter, quickly tighten the stopper and observe it immediately against a black background to see the change in the circumference of the specimen in the test tube.
Identification:
Fresh fish - no white clouds appear, negative reaction (-).
Secondary fish - there was a little white cloud at the instant that the sample was removed from the test tube, but it immediately dissipated. It was a weak positive reaction (+): or after the test sample was placed in a test tube, only after a few seconds there was a clear cloudiness. Positive reaction (++).
Metamorphic fish - After the test sample was placed in a test tube, cloudiness immediately appeared, which was a strong positive reaction (+++).
44, identify the quality of kelp
(1) Good quality seaweed - the color is dark brown or brown green, the leaves are long and wide, and the meat is thick and without roots. There is a slight white powdered mannitol on the surface, with less sand and impurities.
(2) Sub-quality seaweed - The color is yellow-green, and the leaves are narrow and thin. The general sand content is higher.
45. Identify the quality of shark's fin
(1) Good Shark's Fin: Shark's dorsal fin (ridge fin) and pectoral fin (wing). This type of shark fin is huge, with thick and dry fins, a clean surface with a slight sheen and no curling on the edges. Among them, there is a layer of fat-like meat in the ridge wing, and the fins are layered in the meat, which is rich in gelatin. Wings are thin, short fins, fresh texture.
(2) Sub-quality shark fins: The shark's caudal fins (tail fins) are short and thin.
46, identify the quality of bird's nest
The bird's nest is a nest of swiftlets on the island, and dried products made by manual collection and cleansing, and shark fins and sea cucumbers are listed as three kinds of expensive dishes.
The quality of commodity bird's nests is divided into three levels. The first-class product is a red "blood bird's nest". The output is extremely small and extremely valuable. The second-class product is a white "white bird's nest" with a white color and a thick texture with less hair. Other products are "bird's nests" containing a large amount of feathers and impurities.
The quality bird's nest is of good color, white in color, transparent in texture, thick in sac, and less in impurities. It can maintain the original ear shape. The color is yellow or gray, the capsule is thin and the quality of impurities is relatively poor, and the rise is small. The color is gray and the quality of the hair is the worst.
47. Identify the quality of scallops
Scallops are dried seafood products made from scallops, shells from Riyuebei and Jiangbei, processed and dried. Each shellfish can only take a small piece of muscle, such as scallop processed by Jiangbei, with a slightly stripped shape, large, and high protein, sugar, and phosphorous content. The scallops are produced in the coastal areas of China, among which Shandong Rongcheng has the best quality.
48. Identify the quality of dried abalone
Abalone, also known as the general cap, ear shell. The shell is strong, hidden inside the shell, and the foot is quite developed. Abalone is flat and elliptical, with yellow and white color and no bones. The types of abalone in seafood include large abalone, variegated abalone and abalone.
The abalone is dry and dry in texture. It is an oval-shaped ingot shape. There is a ring of flowers on the edge, the middle is convex, and the shape is complete. No impurities and taste are the top grades. The abalones sold in the market include three kinds of dried products: purple abalone, bright abalone, and gray abalone. The purple abalones are large in size and are purple, bright and of good quality. The abalone are large in size, the color is yellow, and the quality is good. Small individuals, dark gray color, quality times.
49. Identify the quality of dried squid
The quality of dried squid is generally graded based on size, luster, color, and meat thickness.
(1) First-grade products: pink flesh, bright and smooth, large body, thick flesh, complete body shape, dry texture, no mold, each body length is more than 20 cm.
(2) Secondary products: pink flesh, bright and smooth, large body, thick flesh, complete body shape, dry texture, no mold, each body length in 14 to 19 cm.
(3) Third grade products: pink flesh, slightly bright and smooth, small body, thin flesh, and relatively complete body shape, each body length is 8 to 13 cm.
The size of the oilhead in China and the hanging piece in Kowloon are of excellent quality and the best sales.
50. Identify the quality of dry sea rice
(1) Color: The body surface is bright and shiny yellow or light red for the top grade, this kind of shrimp are sunny drying, mostly pale. Dark and unclean, it is air-cured on rainy days, and it is generally salty.
(2) Body shape: The shape of shrimp is curved, indicating that it is processed with live shrimp. The shrimps are straight or not very large in shape, and most of them are processed with dead shrimps. Body meat fat, no skin, no claws, no top shell for the top grade.
(3) Impurities; shrimps are well-proportioned, with no impurities and other fish and shrimp as top grade.
(4) Taste: Take a shrimp and chews it in the mouth. It is fresh and slightly sweet. Salt quality is of poor quality.
51, identify the quality of mussels
Mussels sold on the market are divided into four grades by size.
(1) Small mussels: Also known as purple mussels. The smallest figure. As large as beans, the southern region is mostly soaked with boiling water, and can be eaten raw or seasoned before eating.
(2) Mussel: Its size is the size of a jujube.
(3) Large mussels: Their size is as big as jujube.
(4) Extra large mussels: The largest body size is about 50 grams per 3 dry products.
The quality characteristics of dried mussels are oblate, with middle seams, small hairs on the outside, and black and yellow color. When purchasing, it has a large body fat, brown color, shiny, uniform size, dry texture, fresh taste, no crushing and impurities for the top grade.
52. Identify the quality of fish maw
Maw is a seafood product made from dried snails of sea fish and dried by rinsing. The common fish maw on the market is yellow fish maw, scorpion belly belly, wide belly, Mao Chang belly and so on.
The fish belly is generally straight and large, with a thick body, bright color, and a complete body shape. The body is small and thin, and the color is dark. The shape is not complete, and the color is black, indicating that it has deteriorated and cannot be eaten.
53. Identify the quality of the skin
Fish skin is a dried seafood product processed with shark and yellow croaker skins. It is one of the most famous seafood dishes in China because of its high quality, high nutritional value and economic value.
The method of distinguishing the quality of fish skins is mainly to observe the clarity, color and thickness of fish skin inside and outside the skin.
(1) The inner surface of the fish skin: It is known as the side without sand, no residual meat, no residual blood, no dirt, no holes, transparent skin, thick cortex, white color, without salty taste for the top grade. If the color is dark and has a salty taste, it is a defective product, and it is not easy to rise when it is foamed. If the color is red, that is, it has deteriorated and decayed, it is called oil skin and cannot be eaten.
(2) Fish skin surface: The surface of the fish skin is commonly known as sand-bearing. The color is grayish yellow, greenish black or pure black. It is rich in smooth skin, and the sand on the surface is easy to remove. This kind of skin has the best quality. If the surface of the skin is patchy, the sand is difficult to remove and the quality is poor.
54, identify the quality of dry
Dried oysters are dried seafood products made with fresh oyster meat. There are the following three levels:
(1) Daqigan, made from larger gongs, is shaped in a rectangular shape with a sharp tip and golden color. Qidong County has the highest yield.
(2) Stem dry: The body length is about 25 mm, and the body is long-shouldered. There are two small apexes on the head (ie, the outlet pipe and the inlet pipe for drying the stems). Its quality is lower than that of Dabangan, and the yields in Fujian and Zhejiang are many.
(3) Japan's dryness: Its quality is the same as that of a large, dry, round body, and its quality is not as good as that of our country.
Good quality and dry, individual large and complete, meat hypertrophy, light yellow color, dry texture, smell clear, less salty, no broken, no sediment impurities. Poor quality pods dry, small individuals, incomplete shape, dark dull dark brown, mud stuck on the surface, salty smell, smell is not correct.
55, dried seafood products sometimes change the color factor
The change of dry seafood products is a common phenomenon. This is due to the poor storage of dry products or the prolonged storage time, resulting in reddening of flesh color and changes in flavor. People call it change. This is a deterioration that occurs most easily in storage of dry products containing salt and is caused by the proliferation of some salt-tolerant bacteria that produce iodine. To prevent variability, dry products should be stored in low-temperature or relatively dry warehouses. The packaging should be intact and kept out of contact with moist air. During the processing, attention should be paid to the cleaning of salt, barrels and other equipment to reduce the infection of salt-tolerant bacteria. If necessary, disinfect with a bleach solution. During storage and storage, it is necessary to intensify the inspection and early detection, and strive to quickly turn over the sun in the initial period of redness to reduce the water content of the fish, that is, to effectively prevent the redness of dried seafood products.
56. Reasons why seaweed dried products sometimes taste bad
After the dried products have been stored for a long time, they often produce special hazel flavors. This is due to the oxidation of fat in the fish body in the air, resulting in a special bitter and astringent taste and slight odor, yellow or brown color, affecting the product appearance and food quality. The method to prevent dry products from appearing in the processing and storage is: For the varieties with more oil and fat, such as during dry processing in the summer, they should be temporarily placed in a cool place at noon to prevent fat oxidation caused by sun exposure, such as artificial drying. Also try to lower the temperature as much as possible to avoid subcutaneous fat oozing out of the surface and increasing the extent of the gallbladder. The dried products containing more fat that are supplied throughout the year should be stored in cool, ventilated, low-temperature and dry warehouses as much as possible, and more fatty pickled products should be stored with brine.
57. Method for mildew-proof in dried seafood products
Dried seafood products are prone to insect pests during storage, and cause serious damage to the product when it is severe. Insect pests of dry products mainly include insects such as Insecticides and Decapods. In storage, first of all to prevent the breeding of insect pests in the warehouse, and often pay attention to maintaining the cleanliness of the warehouse. Sulfur or other appropriate insecticides should be used for fumigation and pest control before stocking in the warehouse. For products that have been pest-infested, they should be promptly sun-dried and beaten to allow the insects to be exposed and eliminated. Where there is a cold storage facility, pest-infested products should be stored in a cold store so that insect pests can be effectively prevented.
58. Principles of Sensory Identification and Consumption of Aquatic Products and Aquatic Products
Since aquatic products contain high levels of protein and water, aquatic products are also rich in protein, and due to the high activity of enzymes in aquatic crystals and the high pH of their bodies, they are easily contaminated by microbial growth and reproduction. So quickly spoilage. Therefore, the quality of aquatic products and aquatic products, especially their freshness, is relatively high. The sensory identification has determined that the grade of aquatic products and their products should be consumed or processed according to the following principles:
(1) Fresh aquatic products or good quality aquatic products are not restricted and can be freely sold for consumption. However, the marketed astragalus, soft-shelled turtle, turtle, crab, blue crab, crab, small crab and various shellfish should be sold fresh. No one who has died can be sold or processed.
(2) Sub-fresh or sub-quality aquatic products should often be sold immediately for consumption. It should be sold out at a strictly limited time, and must not be stored. If any further deterioration is discovered, it should be treated as corrupt food.
(3) Metamorphic aquatic products and their products are prohibited from consumption or used as raw materials for food processing. According to the degree of corruption, it can be processed into feed, fertilizer or destroyed.
59. Identification of artificial jellyfish and natural jellyfish
Artificial sea bream is made mainly of sodium alginate and gelatin, and then seasoned. The color is slightly yellow or milky white, brittle and lacks toughness, easy to break when pulled, and the mouthfeel is rough, such as chewing pink skin and slightly astringent. Natural jellyfish is a sea jellyfish root jellyfish, which is then marinated and marinated. The appearance of the jellyfish is milky white, yellowish-yellow and pale yellow, and the surface is moist and shiny. When pulled, it is not easily broken, and when it is bitten, it makes a sound. It has toughness and its shape is naturally round without breaking edges.
60, the identification of crab meat and artificial crab meat
Crab meat is a more expensive food, and its supply is insufficient. Some people use cheap salmon meat to make artificial crab meat. Although the nutritional value hasn't changed much, the prices are much different. The fake crab meat is fake and it causes economic losses to consumers.
Identification principle: Squid meat can show obvious colored stripes under focused beam irradiation. In addition, salmon, squid, squid, sea bream, and pike can also display colored patterns. Crab and shrimp do not produce this phenomenon.
Procedure: Spread the sample thinly on the microscope slide, cover it with a similar slide, attach the ends with a rubber band, and place the slide in the light beam emitted by the B&L Nicollas. Samples, such as salmon or other fish processed or mixed with other fish, show colored stripes or patterns. However, crab meat that has not been mixed with fish has no such phenomenon.
61. Identification of cultured shrimp and shrimp
At present, the aquaculture industry has developed rapidly, especially shrimp farming has developed rapidly. There is little difference in nutrient composition and chemical composition between cultured shrimp and wild sea shrimp, but the taste of sea shrimp is better than that of cultivated shrimp, and the aftertaste is long. Therefore, the price of sea shrimp is much different when the shrimp are of the same size and the same freshness. Some traders make use of the lack of discriminating ability of consumers to breed shrimp that poses as sea shrimp. The appearance of the same species of shrimp is quite different. The culture of shrimp needs to be very long, and the shrimp must be short. Sharp and soft texture, while the head of shrimp caught in the ocean is short, blunt, and hard.
Sensory identification of aquatic products and their quality is mainly based on the body surface morphology, freshness, color, smell, meat elasticity and cleanliness and other sensory indicators for comprehensive evaluation. For aquatic products, the first is to observe how their liveliness and whether they have a certain vitality; the second is to look at the integrity of the appearance of the body, pay attention to the presence of scars, detached claws, separation of flesh and meat, etc.; again observe the body The degree of cleanliness of the table is the presence or absence of filth and impurities. Then it is to look at its color, smell its smell, and taste its taste if necessary. In summary, the sensory evaluation was performed again. For aquatic product education, the sensory identification is mainly the appearance, color, smell and taste. Whether or not it has the typical normal smell and flavor of the product is of great significance in making a correct judgment.
2, identify the quality of fresh fish
In the sensory identification of fish, first observe their eyes and blemishes, then check their body and scales, and at the same time, use a clean absorbent paper to absorb the mucus on the scales to observe and smell, to identify the quality of mucus. If necessary, use a bamboo stick to pierce the fish, smell it immediately after pulling it out, or cut a small piece of fish and measure the smell and taste of the fish soup after boiling.
(1) Eyeball identification
Fresh fish - The eyeballs are full and the cornea is transparent and clear and elastic.
Secondary fish - the eyeball is not prominent, the cornea is wrinkled, slightly turbid, and sometimes red blood inside the spill.
Corrupt fish - The eyeball collapses or dries, and the cornea shrinks or breaks.
(2) Identification of fish gills
Fresh fish - The silk is clear and bright red. The mucus is transparent. It has salty smell of sea fish or earthy smell of freshwater fish.
The second fish - dark reddish gray or gray purple, mild mucus odor, bad smell.
Corrupt fish - brownish or grayish white, dirty mucus with an unpleasant rancid odor.
(3) Body Surface Identification
Fresh fish - transparent mucus, scales shiny and closely attached to the fish body, not easy to fall off (except wolfberry, large yellow croaker, small yellow croaker).
Sub-fresh fish - more mucous opacity, scales poor gloss and easier to fall off, mucus sticky and cloudy.
Corrupt fish - body surface dull, with dirty mucus on the surface, scales and fish skin depleted, with rancid odor.
(4) muscle identification
Fresh fish - the muscles are firm and elastic, the depression disappears immediately after the finger pressure, there is no odor, and the muscle section is glossy.
Fresh fish - muscles are slightly loose, the depression disappears slowly after acupressure, slight odor, and shiny muscle section.
Corrupt fish - loose muscles, easy to separate from fish bones, depression formed by finger pressure can not be restored or fingers can pierce the fish.
(5) Identification of abdominal appearance
Fresh fish - normal abdomen, no swelling, white anal hole, depression.
Fresh fish - abdominal swelling is not obvious, slightly protruding anus.
Corrupt fish - The abdomen swells, softens, or ruptures, with dark gray or light green spots on the surface, and the anus protruding or broken.
3, identify the quality of frozen fish
After the fresh fish is frozen at a low temperature of -23°C, the fish body becomes hard and its quality is not as easy to distinguish as fresh fish. The identification of frozen fish should pay attention to the following aspects:
(1) Body surface: good quality frozen fish, bright color and fresh fish-like bright, clean surface, anal tightening. Poor quality frozen fish, dark dull surface, protruding anus.
(2) Fish eyes: Frozen fish with good quality, full eyeballs protruding, cornea transparent, clean without dirt. Poor quality frozen fish, the eyeball is flat or slightly depressed, and the cornea is turbid and white.
(3) Organization: Good quality frozen fish, complete body shape, with a knife to open the inspection, the meat is not strong sting, there is no red line at the spine, the gallbladder is not broken. Poor quality frozen fish, incomplete in shape, cut open with a knife, loose flesh, stabbing phenomenon, gallbladder rupture.
4, identify the quality of salted fish
(1) Color identification
Good quality salted fish - fresh and shiny.
Substandard salted fish - the color is not bright or dark talk.
Inferior salty fish - yellow or red on body surface.
(2) Body surface identification
Good quality salted fish - complete body surface, no broken belly and flesh and meat separation, flat shape, no residual scales, no dirt.
Sub-alkali salted fish - The fish is basically intact, but there may be a small amount of red or mild deterioration, a small amount of residual scales or dirt.
Inferior salted fish - incomplete body surface, separated flesh, debris and dirt, there are mildew phenomenon.
(3) muscle identification
Good quality salted fish - succulent and firm, elastic.
Substandard salted fish - slightly softer and less elastic.
Inferior salted fish - loose meat easily scattered.
(4) Odor identification
Good quality salted fish - with the unique flavor of salted fish, moderate salty.
Substandard salted fish - can have mild odor.
Inferior salted fish - has a significant rancid odor.
5, identify the quality of dried fish
(1) Color identification
Good quality dry fish - clean and shiny appearance, no salt on the surface, white or light fish
Sub-quality fish - poor appearance gloss, darker color.
Inferior dry fish - dull, dull, dull, reddish or grayish, yellow-brown, yellowish.
(2) Odor identification
Good quality dry fish - with the normal flavor of dried fish.
Substance dried fish - may have a slight odor.
Inferior dried fish - with sour, fatty acid or corrupt odor.
(3) Identification of organizational status
Good quality dried fish - complete fish, dry feet, good flesh toughness, smooth, crack-free, broken and incomplete at the cutting edge.
Sub-quality dry fish - the appearance of the fish is basically perfect, but the meat is less tough.
Inferior dry fish - loose meat, cracked, broken or incomplete, high moisture content.
6, identify the quality of yellow croaker
The quality of yellow croaker is generally distinguished from the fish's body surface, fish eyes, fish gills, muscles, and mucous cavity.
(1) Body surface: Fresh and well-rounded yellow croakers are golden yellow and shiny on the body surface. The scales are complete and not easy to fall off. Fresh yellow croakers are pale yellow or white, with poor luster, incomplete scales and easy to fall off.
(2) Fish gizzards: fresh large yellow croakers, bright red or purple red, small yellow fish mostly dark red or purple. Odorless or fishy odor, clear silk. Fresh yellow croakers are dark red, dark purple or brownish yellow and grayish red. They have rancid odors, but they have no foul odor and sticky silk.
(3) Fish eyes: fresh and well-rounded yellow croakers, full of convex eyes, and transparent cornea. Fresh yellow croaker, flat or slightly depressed eyeball, slightly cloudy cornea.
(4) Muscles: Fresh and well-rounded yellow croakers are firm and elastic. Fresh yellow croakers have loose muscles and poor elasticity. If the belly is soft or crooked, it is a metamorphic yellow croaker.
(5) Liquid cavity: Fresh and good yellow fish, the mucus is bright red. Fresh yellow fish, mucus cavity pale red.
7, identify the quality of the fish
The quality of striped fish can be identified from the following aspects:
(1) Body surface: The quality of octopus is good, the body surface is shiny, the whole body is full scale, the scales are not easy to fall off, the wings are all full, and there is no phenomenon of breaking belly and breaking the head. Poor quality octopus, poor surface gloss, scales easily fall off, the body only a few silver phosphorus, the fish body becomes fragrant gray, there are broken belly and broken phenomenon.
(2) Fish eye: Good quality octopus, full eyeball, and transparent cornea. Poor quality of octopus, the eye slightly collapsed, the cornea was slightly turbid.
(3) muscles: good quality octopus, thick muscles, elastic. Poor quality octopus, weak muscles, poor flexibility.
(4) Quality: Good quality octopus, each weighing 0.5 kg or more. Poor quality octopus, each weighing about 0.25 kg.
8, identify the quality of carp
The squid is a saltwater fish. It is also known as white bream, flat fish, mirror fish, car fish, and silver bream. The weight of the carp can be observed from the body surface, fish gills, fish eyes, muscles and other parts.
(1) Body surface: The quality of the carp is good, the scales are close to the fish body, and the fish body is firm and shiny. Poor quality squid, scales are easy to fall off, fish body is less shiny or dull.
(2) Fish gizzards: The gills are of good quality, the gills cover are opened, and the spittoons are purplish red or red with clear and bright quality. The gills are dark purple or grayish red, with turbidity and slight odor.
(3) Fish eyes: Good quality carp, full eyes, and transparent cornea. Poor quality squid, eyeball depression, cornea more sticky.
(4) Muscles: The quality of the carp is good, the meat is dense, and the hand touch elasticity is good. Poor quality squid, loose meat, poor hand touch flexibility.
(5) Gender: The female is large and fleshy. The male body is small and the meat is thin.
9, identify the quality of carp
The squid is also known as the phoenix, the scorpion, the tail fish, and the croaker. It is a kind of Jianghai migratory fish that grows in the ocean and reproduces fresh water, especially in the Yangtze River. Carp is characterized by a narrow and flat body, with anal fins and caudal fins connected together. There are five beards on the pectoral fins. The tips are small, and the color is silver and white, resembling a sharp knife. Squid is a rare fish. Its meat is tender, soft and delicious.
The quality of carp can be checked from the body surface, fish gills, fish eyes, and smell.
(1) Body surface: Good quality carp, scales close to the fish, shiny. Poor quality carp, scales loose, easy to fall off, poor surface gloss.
(2) Fish gizzards: The gills are of good quality, and the gill cover is opened. The gill filaments are yellow and clear and bright. Poor quality squid, cocoon pale yellow, and adhesion phenomenon.
(3) Fish eyes: Good quality carp, full eyeball, clear and transparent. Poor quality carp, with flat or slightly sunken eyes, slightly turbid.
(4) Odor: Good quality carp, no smell. Poor quality squid smells.
10, identify the quality of carp
The squid is a saltwater fish. It is also known as squid, blue-and-white mackerel, oil tube fish, squid, and flower pots. The quality of carp can be checked from the body surface, fish gills, fish eyes, muscles and other parts.
(1) Body surface: Good quality carp, shiny, and clear texture. Poor quality carp, poor surface gloss, visible texture.
(2) Fish carp: The quality carp is good, the carcass is dark red, no peculiar smell, there is a transparent and uniform mucus covered, clear silk. Poor quality of the fish, the body was dark purple or grayish brown, slightly odor, silk adhesion.
(3) Fish eyes: Adhered carp, full eyeballs, and transparent cornea. Poor quality squid, flat or depressed eyeballs, cornea sticky turbidity, and some red eyes.
(4) Muscles: Good quality squid, firm meat, and elastic hands. Poor quality carp, loose flesh, poor hand touch flexibility, if the belly soft yellow, belly broken, paste mouth, etc., indicating that the fish body is poisonous, people eat swollen body. ,
11, identify the quality of carp
Carp is one of the most important economic fishes in the world. There are catfish production in the Yellow Sea and Bohai Sea in China. The quality of carp can be identified from the body surface, fish gills, fish eyes, muscles, anus and other parts.
(1) Body surface: The quality of the squid is good. The back is black and shiny. Poor quality carp, poor luster, back dark black.
(2) Fish gills: Good quality trout, bright red color, and clear silk. Poor quality fish, dark red or dark purple, sticky silk, have stench.
(3) Fish eye: The quality of the carp is good, the eyeball is full and convex, and the cornea is transparent. In poor quality salmon, the eyeball is flat or slightly depressed, and the cornea is cloudy.
(4) Muscles; good fish are of good quality and have elastic hands. Poor fish, loose flesh, poor hand touch flexibility.
(5) Anus: Good quality fish, the anus is in a tight state. Poor quality, the anus protrudes outward.
12, identify the quality of carp
The squid, also known as naked quail, is produced in Qinghai Lake and is a valuable fish with high economic value. Quality can be differentiated from fish gills, fish eyes, muscles and abdomen.
(1) Fish gizzards: The trout with good quality, bright red silk, and clear mucus have the inherent odor of salmon. Poor quality squid, gray silk red, slightly muddy mucus, smell a little smelly.
(2) Fish eyes; good quality carp, full eyeball protrusion, corneal transparency. Poor quality carp, the eye is convex or flat, and the cornea is slightly turbid.
(3) Muscle: Good quality squid, firm meat, good touch of hand touch. Poor quality carp, loose meat, poor hand touch flexibility, there is a stabbing phenomenon.
(4) Abdomen: The quality is good, the abdomen does not swell, and the anus tightens. Poor quality squid, abdomen swells or breaks belly, bowel overflows, and the anus protrudes.
13, identify the quality of fish
Pool fish, also known as stick fish. Because of the high yield and good meat quality, it is popular with consumers. Its quality can be identified from the body surface, fish gills, fish eyes, muscles and other parts.
(1) Body surface: Good quality fish, bright shiny, scales intact, not easy to fall off. Poor quality pond fish, poor surface gloss, phosphorus film is incomplete, easy to fall off.
(2) Fish gills: Good quality pond fish, bright red silk, clear. Poor quality pond fish, Bosch color red or purple, silk sticky, no smell or slight foul smell.
(3) Fish-eye: Fish of good quality, full and protruding eyes, and transparent cornea. Poor quality fish, flat or slightly depressed eyeballs, slightly cloudy cornea.
(4) muscles: good quality fish, solid meat, good elasticity. Poor quality fish, loose flesh, poor flexibility.
14, identify the quality of shrimp
The quality of shrimp is distinguished from the aspects of color, body surface, muscle, smell and so on.
(1) Color: Good quality prawns, normal color, yolk show a natural luster in different maturation periods, poor quality of the prawns color red, yolk shows a different dark gray.
(2) Body surface: Good quality prawns, shrimp bodies are clean and intact, there is no shedding of shells and tails, shrimp tails are not discolored or have slight discoloration, poor quality shrimps, incomplete shrimp bodies, and body dark spots The shells and tails fell off, and the tails were discolored.
(3) muscle: good shrimp, muscle tissue is firm, hand touch elasticity, poor quality shrimp, muscle tissue is loose, poor hand touch flexibility.
(4) Odor: Good quality prawns, smelling normal, no peculiar smell, poor quality prawns, smelling abnormal smells, and generally smelly smells.
15, identify the quality of shrimp
Green shrimp is also known as shrimp, giant shrimp. It belongs to freshwater prawn and it is rich before and after the Dragon Boat Festival. The characteristics of the shrimp are: the head has whiskers, the chest has claws, the two eyes are prominent, the tail is shaped again and again, the body surface is blue, the meat is crisp, and the taste is delicious.
The superiority and inferiority of the quality of the shrimp can be distinguished from the surface color of the shrimp, the degree of head body connection and the muscle condition.
(1) Body color: good quality shrimp, greenish gray, clear and transparent shell. Poor quality shrimp, gray color, poor transparency of the shell.
(2) Degree of head body connection: The shrimp with good quality has a tight head connection and is not easy to fall off. In poor quality shrimp, the head is not tightly connected and is easily detached.
(3) muscle: good quality shrimp, white color, close meat, tail section flexion strong. Poor quality of the shrimp has poor color and whiteness, slightly fleshy texture, and somewhat inferior extension and flexion of the tail section.
16, how to identify the quality of shrimp oil?
(1) Good-quality shrimp oil - Pure shrimp oil is not boiled, the color is clear and not mixed, and the oil is thick. The smell is fresh and fragrant. Salty, light and clean.
(2) Subprime shrimp oil - the color is clear and not mixed, but the oil is relatively thin, and the smell is fresh but there is no rich fragrance. Slightly different salty taste, clean and sanitary.
(3) Inferior shrimp oil - the color is dark and turbid, and the oil is thin as water. The umami taste is not strong and there is no fragrance. The taste is salty and astringent.
17, identify the quality of shrimp paste
(1) Good quality shrimp paste - pink in color, shiny and savory. The paste was thick paste. No impurities, hygienic and clean.
(2) Inferior Shrimp Paste - It is reddish, dull, and smelly. The sauce is thin and not sticky. Mixed with impurities, unsanitary.
18, identify the quality of crab
(1) Body surface identification
Fresh sea crab - bright body surface, back shell texture is clear and shiny. The color of the abdomen's carapace and central sulcus is white and shiny, and no upper part of the umbilicus has stomach marks.
Sub-fresh crabs - surface color dim, poor gloss, abdominal umbilical can appear a slight "blot", ventral central groove darkening.
Corrupted crabs - dark and dull carcasses on the body surface and in the abdomen. Grayish brown spots or plaques in the mid-stomach of the abdomen, or yellow granular rolling substances can be seen.
(2) Identification of Crabs
Fresh sea crab - clear silk, white or slightly brownish.
Sub-fresh crabs - silk is still clear, dark color, no smell.
Corrupted sea crabs - Filament is blurry, dark brown or dark gray.
(3) Identification of limbs and freshness
Fresh Sea Crabs - Live crabs that have just been caught have limbs that are tightly connected and do not sag or droop when the crabs are raised. Live crabs are alert and quick and powerful.
Sub-fresh crabs - live crabs with markedly reduced vitality, are unresponsive, slow and weak. The degree of limb attachment was poor. When the crabs were lifted, the crabs' feet were slightly sagging or distorted.
Corrupted sea crabs - dead crabs that have no life, can no longer be active. The degree of limb connection is very poor. When the crab body is lifted, the crab's feet are perpendicular to the crab's back, and the foot is incomplete.
19, identify the quality of crab
(1) Fresh crabs - Live crabs with strong activity ability. They are sensitive and able to crawl on the palms and feel heavy and heavy.
(2) The fresh crabs - legs and legs, can not turn over when put up, but the crab can move slightly. When you are heavy, you can feel it is good enough.
(3) Inferior crabs - dead crabs that cannot move at all. When weighed, it gives people a sense of emptiness and frivolity.
20. Differentiate the quality of river otters
Fresh river oysters, the clam shell cover is tightly closed, the hand is not easy to open, smell the smell of smelly smell, open the clam shell with a knife, the internal color is bright, the meat is white. If the clam shell does not close tightly, open it by hand, there is a stench of stench, dark gray flesh, it is dead river clams, bacteria are the most prolific, the meat is easy to decompose and produce putrefaction, this clam can not be eaten.
21, identify the quality of oysters
Oyster, also known as jellyfish, is a shellfish mollusk consisting of two left and right shells. The right shell is called the upper shell, the left shell is called the lower shell, and the left shell is attached to the rocks, bamboo, and tiles. The shell moves up and down, feeding, breathing, breeding, and defending the enemy.
Oyster is a delicious shellfish food. Fresh and good quality oysters, full or slightly soft, carious, milky white, body fluids clear, white or light gray, with the inherent smell of oysters. Poor quality oysters, dark in color, bodily fluids are turbid, have offensive odors and are not edible.
Oyster harvest time is generally the most fat winter and spring in the two seasons, the northern production of oysters is small, Guangdong security county production is big.
22, identify the quality of dumplings
The coriander, also known as corrugated, is a special product of our country. Due to the tenderness and deliciousness of the meat, it is considered as a delicacy.
Fresh scorpions, bright shell, two shells tightly closed, easy to open, smell no smell. If the skin of the shell falls off, the shell becomes black and the two shells open, and the smell is offensive, indicating that it is dead and cannot be eaten. At present, some hawkers use shellfish that have been opened to death and use large amounts of mud to make them mistaken for live pigtails.
23, identify the quality of calyx
Fresh flower pods, shells with inherent color, usually open mouth slightly, frightened when two shells close tightly, axe foot and contact tube flexible, with inherent odor. If two shells are open, the feet and the contact tube do not have the ability to stretch, and if they smell strange, they cannot eat it.
24, identify the quality of boiled shellfish
(1) fresh shellfish - normal and shiny color, no smell, hand feel smooth, good elasticity.
Not fresh shellfish - the color is reduced or dull, there is sour, feel sticky, poor flexibility.
(2) Fresh erythrobis - dark yellowish brown or light yellowish brown, shiny, with good elasticity.
Not fresh erythras - grayish yellow or light green, dull, inelastic.
(3) fresh conch meat - milky yellow or light yellow, shiny, elastic, local purple rose spots.
Not fresh conch meat - white or gray, dull, inelastic.
25, identify the quality of the foot
(1) Color identification
Fresh foot - with the inherent fresh color of this species, pigment spots are clear, the body surface is shiny, mucus is more and clear.
Metamorphic foot - pigment spots are blurred, and they appear as a piece of red, with mucus on the surface.
(2) muscle identification
Fresh feet - body meat soft and smooth, elastic.
Metamorphic foot - body fat stiff astringent or excessively soft, inelastic.
(3) Identification of eyeballs and odors
Fresh feet - eyeball full and prominent, shiny, body meat without abnormal smell
Metamorphic foot - eyeball collapsed and dull, with stench.
26, identify squid and squid
(1) How to identify squid and squid by pressing and shape
Press hard on the middle of the corpus callosum with your fingers. If there is a hard feeling, it is a squid fish. If it is soft, it is a carp. Because the squid has a hard, cuttlefish bone like a boat, and the eel has only a leaf-like transparent film that crosses the body, it feels different. In addition, squid are generally slender body shape, the end was a long rhombus-shaped, meat fins are separated on both sides of the corpus callosum, when viewed upside, much like a "marine head", and squid shape slightly shoulder width, and squid The other features are also different.
(2) Quality identification of carp
The common squid on the market has two kinds of elongated and oval. The eel's shape is elongated, the squid-shaped dry product is oval, and it is educated in terms of quality. The elongate shape is superior to the oval shape.
Good quality carp body is thick and solid, body meat is dry, slightly translucent red, no mold. The tender carp is yellowish in color, transparent and thin. The old squid has a purple color and a large body.
27, identify the quality of jellyfish head
The quality of jellyfish heads is divided into two grades.
(1) First-grade products: Complete dried meat, light red color, rich light, crunchy texture, no silt, broken bar and inclusions, no smell.
(2) Second-grade products: The dried meat is complete, the color is red, the light is poor, there is no sediment, but there are a few broken bars and inclusions, and there is no smell.
Before eating jellyfish, check it carefully to avoid causing intestinal diseases. The inspection method is to use two fingers to pick up the jellyfish head, if it is easy to break, the meat is crispy, and the color is purple and black, indicating that it is broken and cannot be eaten.
28, identify the quality of jellyfish
(1) Color identification
Good jellyfish skin - white, milky or light yellow, wet and shiny surface, no obvious red spots.
Sub-seagrass - gray or dark brown, poor surface gloss.
Inferior jellyfish skin - dark gray or blackish on the surface.
(2) Fragile identification
Good quality jellyfish - crispy and resilient, buzzing when chewing.
The sub-quality jellyfish - poor crispness, no toughness.
Bad jellyfish - crisp texture, easy to tear, no brittleness and toughness.
(3) Thickness Identification
Good quality jellyfish - uniform thickness throughout.
Secondary jellyfish skin - uneven thickness.
Inferior jellyfish skin - uneven thickness.
(4) Shape identification
Good quality jellyfish skin - natural round, with no holes in the middle, edges do not break.
Secondary jellyfish skin - incomplete shape, broken phenomenon.
Inferior jellyfish skin - incomplete shape, easy to break.
29, identify fish with illness
Diseased fish can be identified from the following aspects:
(a) The body surface of fish
Generally suffering from sick fish, the muscles on both sides of the body, the base of the fins, especially the base of the anal fins are all congested. According to the different parts of the fish body, there are several kinds of common diseases:
(1) Hemorrhagic disease: The slightly muscular condition of the disease is somewhat straightened: The body muscles with a heavy illness are dark red.
(2) erythroderma disease, the fish's body surface has partial congestion, inflammation, scales off phenomenon.
(3) Print disease: Round ovoid erythema appears on the tail or on both sides of the abdomen. The diseased muscle rots into small pits, showing bones and internal organs.
(4) Fish wind disease: There are pale green spots on the body surface of the fish. The body of the bugs is crawling.
(5) Saprolegnia: on both sides of the fish body, up and down the abdomen and back, etc., there are cotton-like white long hairs.
(6) Trichodiasis: Frigs and fingerlings do irregular scampering along the edge of the pond or on the surface of the water, and there are red spots on the head.
(7) Enteritis: The anus of the fish is red and swollen, with inflammation and congestion.
(8) Ophthalmopathy: The prominent fish eye is caused by high levels of organic acid or ammonia in the water and high nitrogen content.
(B) Silk color
The silk is white, the tip cartilage is exposed, the ends of the silk are uneven, and the mucus is more. The cocoon silk is arranged irregularly with purple-red dots, and the white silkworm body at the end of the cocoon wire is Chinese juvenile aphid disease. The silk surface is light white with bumpy spots. It is a trichoderma or a pseudoflagellate disease.
(c) Intestinal color
Peel the fish off to observe the intestine. If the intestine is completely or partially reddish, the thickness is not uniform, and the meat has beige mucus, it is bowel disease. If the intestine of the herring is white, the front end is swollen, and there are many white cotton-like nodules on the inner wall of the intestine, it is coccidiosis.
30. Identify poisoned fish
In farmers' markets, fish that are poisoned by pesticides are often sold. When buying, pay special attention. Poisonous fish should be identified from the following aspects:
(1) Fish mouth: After the normal fish dies, the closed mouth can naturally open. Poisonous fish, fish mouth closed, not easy to pull naturally.
(2) Fish gizzards: Fresh fish that normally die, and its pod color is bright red or reddish. Poisonous fish, purple or brown red.
(3) fins: Normal dead fish with membrane fins close to the abdomen. Poisoned fish, pelvic fins open and hard.
(4) Odor: Normal dead fish, there is a fish smell, no other smell. Poisoned fish can smell a bit of pesticide from fish bladders, but it does not include odorless pesticides.
31. Identify contaminated fish
Because rivers and lakes are affected by the discharge of industrial waste water, they cause fish to be contaminated and die, and these contaminated fish are often sold on the market. The identification of contaminated fish has the following aspects:
(1) posture: contaminated fish, often deformed, such as the head and tail small, or head small tail, abdomen made soft, spine bent, fish scale color yellow, red or blue.
(2) Fish eyes: Contaminated fish. The eyeballs are cloudy and dull, and some of the eyes protrude outward.
(3) Fish gills: Contaminated fish gills have a dull colour and usually have a whitening majority.
(4) Odor; Contaminated fish, generally smells of ammonia, kerosene, hydrogen sulfide, etc., lack fishy smell.
32. What part of puffer fish contains toxins?
Puffer fish toxins are mainly found in the ovary and liver, followed by kidneys, blood, eyes, fish gills, and fish skin. Some puffer fish also contain toxins in their meat. During the winter and spring, ovarian toxins are the most toxic. If people eat a piece of fish like a finger, they will be poisoned.
33. Which part of the carp contains toxins?
The squid is also known as squid and mackerel. The blood of this fish is black. After the cut of the fish's back, there is a blood line. The blood line is poisonous. If the fish is washed, the blood line will not be removed. Cooking and eating with the fish will cause the body to produce Allergy phenomenon, if the fish's abdomen is soft yellow, broken belly, paste mouth, etc., indicating that the fish has deteriorated and spoiled, if people eat this fish, will make the body swollen.
34. Which parts of the carp are toxins?
The squid is also known as Blue Point Horse Hinge, Blue Point Stork, and Swallow Fish. Its quality is characterized by less spiny meat, garlic-shaped flesh, more tender. However, the liver of this fish contains toxic substances and cannot be eaten. Therefore, the fish liver must be removed when cleaning the fish.
35. Which part of the pond fish has toxins
The fish is also known as blue round, stick fish, barb fish, pool fish and so on. This fish should be fresh and safe. If released for a long period of time, histidine in the fish will decompose rapidly and produce toxic ammonia. If people eat this fish, food poisoning will occur.
36, which part of the carp contains toxins
The squid is also known as squid, squid, and beard. It is a kind of freshwater wild fish, which is distributed in Heilongjiang River, Yellow River, Yangtze River and Pearl River Basin in China. It is a kind of fish with rich nutrition and tasty meat. However, when cleaning this fish, be sure to remove the eggs, because it is toxic and inedible.
37. Which part of the carp contains toxins?
The squid is also known as white cricket, scorpion, bitter chain and so on. It is a common freshwater fish, which is common throughout the year in the farmers' market in the Mainland. It is a popular and inexpensive fish. When people wash this fish, they need to remove the fish liver because it contains Poisonous to prevent food poisoning.
38. Which part of the carp is poisoned?
Squid is produced in Qinghai Lake. The viscera and eyes of this fish are poisonous. When cleaning fish, the internal organs and eyes must be removed to prevent food poisoning.
39. Which part of the river turtle contains toxins?
The river clams are also known as cockroaches, eel, and white cockroaches. The fish's serum contains toxins, wound fingers, do not come into contact with the river blood, in order to prevent wound inflammation, suppuration.
40. Why did Huang Fei eat food?
Astragalus also known as carp, long fish and so on. In the private sector, there is a saying that "Summer Yellow Ginseng Race Ginseng" is said to be popular today. However, one thing to note is that squid can only eat fresh, slaughter is cooking, and should not eat dead stingray. Because the histidine contained in the body will quickly turn into toxic histamine after the death of the stingray, people will cause food poisoning after eating. The blood serum of Astragalus contains toxins. If there are wounds on the fingers of the people, once they come into contact with the blood of the fish, the wounds will become inflamed and purulent.
41. Why can't eat dead turtle?
The soft-shelled turtle is also known as the group of fish. Due to its tender meat, rich flavour and rich nutrition, the soft-shelled turtle is considered to be a tonic. However, dead turtles cannot eat. Since soft-shelled turtles contain more histidine, histidine is an important ingredient that has a special umami taste, and it can produce histamine after decomposition. Histamine is a strong straight tube expander, which can cause the release of a series of allergic substances. When the concentration is too high, it can cause symptoms such as prostration and shock. After the death of the soft-shelled turtle can be self-decomposition to produce ammonia, people eat dead turtles, it will cause food poisoning.
42. Sensory identification of fresh aquatic products after boiling experiments
For aquatic products that are slightly less or have a slight odor, when the sensory identification method is used to determine the freshness of the product, it is possible to smell the odor and taste the taste after the brew test, and identify with the observation of the soup. When boiling test, the sample is generally not more than half a kilogram, and the amount of water discharge is appropriate to just immerse the sample. First, the water in the container is boiled, and then the sample of the deceased person and the lid of the container are heated. When the bottle is boiled again, the heat source is removed, and then the lid is opened for identification.
(1) Odor identification
The scent of fresh products - with the inherent flavor of this species.
The odor of deteriorating products - there is a stench or ammonia smell.
(2) Identification of taste
The taste of fresh products - This product has a delicious taste that is inherent in this product. The texture of the meat is elastic.
The taste of the deteriorating product - no umami, fleshy hair, ammonia odor.
(3) Soup Identification
Fresh soup - soup clear, with the color of this type of pigment, no minced meat in the soup.
Deteriorated soup - turbid soup, fleshy spoilage suspended in the soup.
43. Rapid test of freshness of aquatic products
(1) Determination of pH
Operation: The same pH value as in the meat freshness test.
Identification: fresh fish - pH 6.5 ~ 6.8.
Fresh fish - The pH is 6.9-7.0.
Metamorphic fish - the pH is above 7.1.
(2) Hydrogen Sulfide Measurement Operation: Weigh 20 grams of sample fish into a small jar, add 40 ml of 10% sulfuric acid solution, and place a square or round filter paper larger than the bottle mouth in the middle of the filter paper block. Drop 1 to 2 drops of 10% lead acetate alkaline solution, and then place the drop with one side down on the bottle mouth and use a rubber band. After 15 minutes, remove the filter paper and observe the color change.
Identification:
Fresh fish - Lead acetate alkaline solution, no change in color, negative reaction (-).
Fresh fish - Appears slightly brown or brown near the edge of the sputum, as a suspected reaction () or a weak positive reaction (+).
Corrupt fish - all drip sites are brown, darker at the border, positive reaction (+ +), or dark brown, strong positive reaction (+++).
(3) Determination of ammonia
Operation: Take a large piece of fish meat, hung on a glass rod with a rubber stopper attached to the other end with a hook, and use a pipette to draw Aibeier's test solution (take 15% of hydrochloric acid with a specific gravity of 1.12 and 1 part of anhydrous ether, 96%). Mix 2 ml of 3% alcohol and inject it into the test tube. After slightly shaking, place the glass rod with rubber stopper into the test tube (be careful not to touch the wall) until the sample is 1 to 2 feet away from the liquid surface. At a centimeter, quickly tighten the stopper and observe it immediately against a black background to see the change in the circumference of the specimen in the test tube.
Identification:
Fresh fish - no white clouds appear, negative reaction (-).
Secondary fish - there was a little white cloud at the instant that the sample was removed from the test tube, but it immediately dissipated. It was a weak positive reaction (+): or after the test sample was placed in a test tube, only after a few seconds there was a clear cloudiness. Positive reaction (++).
Metamorphic fish - After the test sample was placed in a test tube, cloudiness immediately appeared, which was a strong positive reaction (+++).
44, identify the quality of kelp
(1) Good quality seaweed - the color is dark brown or brown green, the leaves are long and wide, and the meat is thick and without roots. There is a slight white powdered mannitol on the surface, with less sand and impurities.
(2) Sub-quality seaweed - The color is yellow-green, and the leaves are narrow and thin. The general sand content is higher.
45. Identify the quality of shark's fin
(1) Good Shark's Fin: Shark's dorsal fin (ridge fin) and pectoral fin (wing). This type of shark fin is huge, with thick and dry fins, a clean surface with a slight sheen and no curling on the edges. Among them, there is a layer of fat-like meat in the ridge wing, and the fins are layered in the meat, which is rich in gelatin. Wings are thin, short fins, fresh texture.
(2) Sub-quality shark fins: The shark's caudal fins (tail fins) are short and thin.
46, identify the quality of bird's nest
The bird's nest is a nest of swiftlets on the island, and dried products made by manual collection and cleansing, and shark fins and sea cucumbers are listed as three kinds of expensive dishes.
The quality of commodity bird's nests is divided into three levels. The first-class product is a red "blood bird's nest". The output is extremely small and extremely valuable. The second-class product is a white "white bird's nest" with a white color and a thick texture with less hair. Other products are "bird's nests" containing a large amount of feathers and impurities.
The quality bird's nest is of good color, white in color, transparent in texture, thick in sac, and less in impurities. It can maintain the original ear shape. The color is yellow or gray, the capsule is thin and the quality of impurities is relatively poor, and the rise is small. The color is gray and the quality of the hair is the worst.
47. Identify the quality of scallops
Scallops are dried seafood products made from scallops, shells from Riyuebei and Jiangbei, processed and dried. Each shellfish can only take a small piece of muscle, such as scallop processed by Jiangbei, with a slightly stripped shape, large, and high protein, sugar, and phosphorous content. The scallops are produced in the coastal areas of China, among which Shandong Rongcheng has the best quality.
48. Identify the quality of dried abalone
Abalone, also known as the general cap, ear shell. The shell is strong, hidden inside the shell, and the foot is quite developed. Abalone is flat and elliptical, with yellow and white color and no bones. The types of abalone in seafood include large abalone, variegated abalone and abalone.
The abalone is dry and dry in texture. It is an oval-shaped ingot shape. There is a ring of flowers on the edge, the middle is convex, and the shape is complete. No impurities and taste are the top grades. The abalones sold in the market include three kinds of dried products: purple abalone, bright abalone, and gray abalone. The purple abalones are large in size and are purple, bright and of good quality. The abalone are large in size, the color is yellow, and the quality is good. Small individuals, dark gray color, quality times.
49. Identify the quality of dried squid
The quality of dried squid is generally graded based on size, luster, color, and meat thickness.
(1) First-grade products: pink flesh, bright and smooth, large body, thick flesh, complete body shape, dry texture, no mold, each body length is more than 20 cm.
(2) Secondary products: pink flesh, bright and smooth, large body, thick flesh, complete body shape, dry texture, no mold, each body length in 14 to 19 cm.
(3) Third grade products: pink flesh, slightly bright and smooth, small body, thin flesh, and relatively complete body shape, each body length is 8 to 13 cm.
The size of the oilhead in China and the hanging piece in Kowloon are of excellent quality and the best sales.
50. Identify the quality of dry sea rice
(1) Color: The body surface is bright and shiny yellow or light red for the top grade, this kind of shrimp are sunny drying, mostly pale. Dark and unclean, it is air-cured on rainy days, and it is generally salty.
(2) Body shape: The shape of shrimp is curved, indicating that it is processed with live shrimp. The shrimps are straight or not very large in shape, and most of them are processed with dead shrimps. Body meat fat, no skin, no claws, no top shell for the top grade.
(3) Impurities; shrimps are well-proportioned, with no impurities and other fish and shrimp as top grade.
(4) Taste: Take a shrimp and chews it in the mouth. It is fresh and slightly sweet. Salt quality is of poor quality.
51, identify the quality of mussels
Mussels sold on the market are divided into four grades by size.
(1) Small mussels: Also known as purple mussels. The smallest figure. As large as beans, the southern region is mostly soaked with boiling water, and can be eaten raw or seasoned before eating.
(2) Mussel: Its size is the size of a jujube.
(3) Large mussels: Their size is as big as jujube.
(4) Extra large mussels: The largest body size is about 50 grams per 3 dry products.
The quality characteristics of dried mussels are oblate, with middle seams, small hairs on the outside, and black and yellow color. When purchasing, it has a large body fat, brown color, shiny, uniform size, dry texture, fresh taste, no crushing and impurities for the top grade.
52. Identify the quality of fish maw
Maw is a seafood product made from dried snails of sea fish and dried by rinsing. The common fish maw on the market is yellow fish maw, scorpion belly belly, wide belly, Mao Chang belly and so on.
The fish belly is generally straight and large, with a thick body, bright color, and a complete body shape. The body is small and thin, and the color is dark. The shape is not complete, and the color is black, indicating that it has deteriorated and cannot be eaten.
53. Identify the quality of the skin
Fish skin is a dried seafood product processed with shark and yellow croaker skins. It is one of the most famous seafood dishes in China because of its high quality, high nutritional value and economic value.
The method of distinguishing the quality of fish skins is mainly to observe the clarity, color and thickness of fish skin inside and outside the skin.
(1) The inner surface of the fish skin: It is known as the side without sand, no residual meat, no residual blood, no dirt, no holes, transparent skin, thick cortex, white color, without salty taste for the top grade. If the color is dark and has a salty taste, it is a defective product, and it is not easy to rise when it is foamed. If the color is red, that is, it has deteriorated and decayed, it is called oil skin and cannot be eaten.
(2) Fish skin surface: The surface of the fish skin is commonly known as sand-bearing. The color is grayish yellow, greenish black or pure black. It is rich in smooth skin, and the sand on the surface is easy to remove. This kind of skin has the best quality. If the surface of the skin is patchy, the sand is difficult to remove and the quality is poor.
54, identify the quality of dry
Dried oysters are dried seafood products made with fresh oyster meat. There are the following three levels:
(1) Daqigan, made from larger gongs, is shaped in a rectangular shape with a sharp tip and golden color. Qidong County has the highest yield.
(2) Stem dry: The body length is about 25 mm, and the body is long-shouldered. There are two small apexes on the head (ie, the outlet pipe and the inlet pipe for drying the stems). Its quality is lower than that of Dabangan, and the yields in Fujian and Zhejiang are many.
(3) Japan's dryness: Its quality is the same as that of a large, dry, round body, and its quality is not as good as that of our country.
Good quality and dry, individual large and complete, meat hypertrophy, light yellow color, dry texture, smell clear, less salty, no broken, no sediment impurities. Poor quality pods dry, small individuals, incomplete shape, dark dull dark brown, mud stuck on the surface, salty smell, smell is not correct.
55, dried seafood products sometimes change the color factor
The change of dry seafood products is a common phenomenon. This is due to the poor storage of dry products or the prolonged storage time, resulting in reddening of flesh color and changes in flavor. People call it change. This is a deterioration that occurs most easily in storage of dry products containing salt and is caused by the proliferation of some salt-tolerant bacteria that produce iodine. To prevent variability, dry products should be stored in low-temperature or relatively dry warehouses. The packaging should be intact and kept out of contact with moist air. During the processing, attention should be paid to the cleaning of salt, barrels and other equipment to reduce the infection of salt-tolerant bacteria. If necessary, disinfect with a bleach solution. During storage and storage, it is necessary to intensify the inspection and early detection, and strive to quickly turn over the sun in the initial period of redness to reduce the water content of the fish, that is, to effectively prevent the redness of dried seafood products.
56. Reasons why seaweed dried products sometimes taste bad
After the dried products have been stored for a long time, they often produce special hazel flavors. This is due to the oxidation of fat in the fish body in the air, resulting in a special bitter and astringent taste and slight odor, yellow or brown color, affecting the product appearance and food quality. The method to prevent dry products from appearing in the processing and storage is: For the varieties with more oil and fat, such as during dry processing in the summer, they should be temporarily placed in a cool place at noon to prevent fat oxidation caused by sun exposure, such as artificial drying. Also try to lower the temperature as much as possible to avoid subcutaneous fat oozing out of the surface and increasing the extent of the gallbladder. The dried products containing more fat that are supplied throughout the year should be stored in cool, ventilated, low-temperature and dry warehouses as much as possible, and more fatty pickled products should be stored with brine.
57. Method for mildew-proof in dried seafood products
Dried seafood products are prone to insect pests during storage, and cause serious damage to the product when it is severe. Insect pests of dry products mainly include insects such as Insecticides and Decapods. In storage, first of all to prevent the breeding of insect pests in the warehouse, and often pay attention to maintaining the cleanliness of the warehouse. Sulfur or other appropriate insecticides should be used for fumigation and pest control before stocking in the warehouse. For products that have been pest-infested, they should be promptly sun-dried and beaten to allow the insects to be exposed and eliminated. Where there is a cold storage facility, pest-infested products should be stored in a cold store so that insect pests can be effectively prevented.
58. Principles of Sensory Identification and Consumption of Aquatic Products and Aquatic Products
Since aquatic products contain high levels of protein and water, aquatic products are also rich in protein, and due to the high activity of enzymes in aquatic crystals and the high pH of their bodies, they are easily contaminated by microbial growth and reproduction. So quickly spoilage. Therefore, the quality of aquatic products and aquatic products, especially their freshness, is relatively high. The sensory identification has determined that the grade of aquatic products and their products should be consumed or processed according to the following principles:
(1) Fresh aquatic products or good quality aquatic products are not restricted and can be freely sold for consumption. However, the marketed astragalus, soft-shelled turtle, turtle, crab, blue crab, crab, small crab and various shellfish should be sold fresh. No one who has died can be sold or processed.
(2) Sub-fresh or sub-quality aquatic products should often be sold immediately for consumption. It should be sold out at a strictly limited time, and must not be stored. If any further deterioration is discovered, it should be treated as corrupt food.
(3) Metamorphic aquatic products and their products are prohibited from consumption or used as raw materials for food processing. According to the degree of corruption, it can be processed into feed, fertilizer or destroyed.
59. Identification of artificial jellyfish and natural jellyfish
Artificial sea bream is made mainly of sodium alginate and gelatin, and then seasoned. The color is slightly yellow or milky white, brittle and lacks toughness, easy to break when pulled, and the mouthfeel is rough, such as chewing pink skin and slightly astringent. Natural jellyfish is a sea jellyfish root jellyfish, which is then marinated and marinated. The appearance of the jellyfish is milky white, yellowish-yellow and pale yellow, and the surface is moist and shiny. When pulled, it is not easily broken, and when it is bitten, it makes a sound. It has toughness and its shape is naturally round without breaking edges.
60, the identification of crab meat and artificial crab meat
Crab meat is a more expensive food, and its supply is insufficient. Some people use cheap salmon meat to make artificial crab meat. Although the nutritional value hasn't changed much, the prices are much different. The fake crab meat is fake and it causes economic losses to consumers.
Identification principle: Squid meat can show obvious colored stripes under focused beam irradiation. In addition, salmon, squid, squid, sea bream, and pike can also display colored patterns. Crab and shrimp do not produce this phenomenon.
Procedure: Spread the sample thinly on the microscope slide, cover it with a similar slide, attach the ends with a rubber band, and place the slide in the light beam emitted by the B&L Nicollas. Samples, such as salmon or other fish processed or mixed with other fish, show colored stripes or patterns. However, crab meat that has not been mixed with fish has no such phenomenon.
61. Identification of cultured shrimp and shrimp
At present, the aquaculture industry has developed rapidly, especially shrimp farming has developed rapidly. There is little difference in nutrient composition and chemical composition between cultured shrimp and wild sea shrimp, but the taste of sea shrimp is better than that of cultivated shrimp, and the aftertaste is long. Therefore, the price of sea shrimp is much different when the shrimp are of the same size and the same freshness. Some traders make use of the lack of discriminating ability of consumers to breed shrimp that poses as sea shrimp. The appearance of the same species of shrimp is quite different. The culture of shrimp needs to be very long, and the shrimp must be short. Sharp and soft texture, while the head of shrimp caught in the ocean is short, blunt, and hard.