Is it possible to eat frozen fish if the expiry date has expired
Freezing is a method of canning, withwhich fish is cooled to the lowest temperature possible up to the cryohydrate point of the solution of salts and nitrogenous substances contained in its tissues. Long-term storage of frozen fish depends on the fact that lowering the temperature to -10 ° C or lower sharply inhibits the vital activity of microorganisms and tissue enzymes, slows the oxidative breakdown of fat. In those cases when the fish is intended for transportation and short-term storage, but longer than it is possible with cooling, it is not frozen completely, but from -3 to -4 ° C. This fish is called frozen (supercooled).
In the frozen form, they harvest and sellpractically all kinds of fish. The shelf-life of frozen fish depends on the temperature, and the method of preservation. When storing frozen fish they use boxes of board and cardboard, boxes, barrels, bales of horny,
bags and so on.The packaging must be firm, clean, free of foreign smells. Cover the wooden packaging with wrapping paper. Especially valuable varieties of fish (white fish, nelma, etc.) are individually wrapped in parchment. In each unit of packaging, fish of one kind, type, size, method of cutting and freezing are laid.
According to GOST 1168-86 they store frozen fish on ships, production and distribution refrigerators at a temperature not higher than -18 "C.
The shelf-life of dry artificial and natural freezing fish at -18 ° C is (in months), no more than:
glazed:sturgeon, pink salmon, char - 7; salmon from the Far East (except for pink salmon and char), carp, whitefish, pike perch, perch, pike, catfish, flounder Azov-Black Sea - 8; salmon Baltic undivided and other undivided salmon fishes - 4; salmon Baltic gutted with head and the remaining gutted with salmon head head - 3; cod, flounder, halibut, perch cut and undressed - 6; pollock headless and back - 6; the remaining freshwater - 8; the remaining sea - 6;
treated with aqueous solution of PVS: pink salted - 10;
wrapped in antiadhesion paper: cod, flounder, halibut, perch cut and undressed - 5; pollock headless and back - 4;
unglazed: carp, whitefish, pike perch, perch river, pike, catfish, flounder - 6; cracked broken - undivided - 4; other freshwater fish - no more than 6; other marine fish - 4.
Fish dry artificial and naturalfreezing in consumer packaging at a temperature of not more than -18 "C stored no more than 1 month from the date of manufacture, at a temperature not higher than -10 ° C freshwater - no more than 3 months, sea - no more than 2 months.
To reduce quantitative and qualitativeChanges in long-term storage are covered with tarpaulins, film or other insulating materials. During storage, it is recommended that the fish be inspected periodically, noticing the presence of mold or rust, and if necessary, decide on the implementation.
At the trading enterprises in refrigerators frozen fish is stored at a temperature from -5 to -6 ° C to 14 days, in shops without refrigeration equipment - 1 day, and at a temperature close to 0 ° С, 3 days.
Defects of chilled and frozen fish canbe conditioned by the quality of raw materials received for freezing, and processing technology. They can give foreign fish atypical odors, change appearance, color and consistency.
Drying occurs with significant shrinkagefrozen fish. However, it only loses color, but the meat acquires a dry, hard, fibrous consistency, the aroma of fresh fish disappears, and a sharp fishy smell arises. When drying in meat develops hydrolysis of fat, accompanied by foreign odor.
Deformation frozen fish is possible by freezing itin bulk or untimely overturning. Small deformations of block freezing fish, curvature of the caudal peduncle, fish, frozen on the fly, are not considered vices.
Ice-coldness can worsen the presentation, consistency, smell and taste of fish. This fish can gradually become moldy and putrefy.
Darkening surface may be due to protein denaturation.
Hummocky can appear when filifying the fish before the onset of mortal mortis.
Russet coloration It is possible with poor exsanguination of fish.
TO old smells are stale, warehouse, sharp "fish", "which occur with long-term storage of chilled and frozen fish at high temperature, low humidity and no glaze. In the cooled and frozen fish, the smell of oxidized fat can result from the storage of fish at elevated temperature, the lack of packaging and poor bleeding of fish at the time of cutting, the long-term storage of fish caught without cooling.
Extraneous, atypical odors When the product enters randomsubstances or in case of spoilage. As a result of spoilage, putrefactive and garlic odors may appear, which indicates a profound biochemical change in the tissues of fish. Putrefactive odor is possible when the raw material is reduced in quality. The smell of hydrogen sulfide indicates a protein breakdown of the fish before freezing. At bacterial decomposition of a fish before freezing there is a smell of ammonia.
Smell of oil products fish acquires, when in fishery reservoirs there is a discharge of products of oil refining. Such a fish is not suitable for food.
Loose consistency It occurs when the raw fish is delayed untilfreezing, the development of autolysis in it, slow freezing, when large ice crystals are formed, which destroy the muscle shell and weaken the elasticity of the tissue. Under the same conditions, a flabby, structureless consistency arises.
Stratification of muscular tissue on miosepts can occur during deformation of fish during freezing.
Instability Meat of fish occurs and develops in raw fish.The smelling odors and taste are not formed at the same time. Structurelessness is observed mainly in cambole, mackerel (mackerel, tuna), horse mackerel (horse mackerel), cod (hake, cod, haddock) and salmon (humpback salmon, chum). The cause of this defect is an increased content of volatile bases in nitrogen and high buffering (from 70 to 140 ° C). Buffering of meat in normal condition is from 30 to 40 ° C. Non-structured meat also contains less collagen and elastin than normal-structure meat.
There are known the states of structurelessness of fish meat, which in world fishery it is customary to call milk, gelatinous, curd, lime and simply softened.
Jellyfish (ironiness) occurs when the fish is affectedparasitic organisms (presumably Chloromyxum). The muscle tissue of such a fish has an uneven density, some areas are soft or even liquid. The affected area looks like a bunch of grapes. Immediately after catching the fish, jelly is not observed, it is found after filing.
Milk condition - in the meat of fish, mainly along the back,there are "pockets" filled with milky white liquid, formed from hypertrophied muscle fibers. The reason is the presence of microsporidia from the genus Chloromyxum or other parasites in these "pockets".
Lime condition characterized by lack of transparencytissue juice, lethargic, softened, and sometimes coarsening the consistency of meat with a complete loss of elasticity. In its raw form, such meat resembles boiled. The moisture content decreases markedly with increased amounts of protein and fat. Parasites are absent. Meat in this state only conditionally refers to the structureless.
Commodity evaluation and quality assessment frozen fish are carried out by organoleptic andphysicochemical indicators (GOST 1168-86), microbiological indices (MAFAM, CFU / g 1.6 x 104, Staphylococcus aureus, dysenteric and salmonella groups of microorganisms are not allowed). Limit norms for the content of toxic elements and pesticides are similar to those in chilled fish.
Frozen fish are packed:
• in wooden boxes or in boxes of corrugated cardboard according to the normative document with a maximum product weight of 40 kg. Sardines - in boxes of corrugated cardboard with a maximum product mass of 40 kg;
• Bales of strontium or of canvas sewn non-woven material according to the normative document;
• hemp-jute bags or from canvas sewn non-woven material with a maximum product weight of 40 kg;
• in film bags, packs of cardboardparaffined or with polymer coating, cardboard packages without coating with preliminary packaging of fish in film bags according to the normative document with a maximum product weight of 1.0 kg.
Packages and bundles with products are packed in boxes of corrugated cardboard or wooden boxes with a maximum product weight of 30 kg.
Frozen fish are packaged in film bags inaccording to the instruction. Transport packaging and packaging for products sent to the Far North and hard-to-reach areas must comply with approved requirements.
Wooden boxes before packing frozen fish are lined with dense wrapping paper.
Containers for packaging frozen fish should be strong, clean, free of foreign smell.
Blocks of frozen fish, except for blocks packed infilm bags or wrapped in release paper, when placed in boxes, they must be transferred with parchment, sub-parchment or other liquid-impermeable materials or packed in film inserts from film materials according to the normative document.
Blocks can be transferred with dense wrapping paper.
Blocks of frozen fish (except for sardines) can be laid without gaskets.
In each packaging unit, there must be a fish of one denomination, variety, type of cutting, one size group and the type of consumer packaging.
For fish not subdivided by length and mass, not more than 10% of fish (in the account) are allowed in each unit of the transport container less than the established minimum length.
For subdivided by length or mass of large and medium sized fish, not more than 2 fish specimens are allowed in each unit of the transport container, and in the case of medium - longer length or weight.
For subdivided by length or mass of small fishit is allowed in each unit of the transport container not more than 2% of the fish (according to the account) of a greater or lesser length or mass. Fish-a trifle of the third group can be laid without division by species of fish. Wooden boxes with products are clogged and fastened on the front sides by steel packing tape or steel wire.
Boxes from corrugated cardboard tightly tightensteel packing tape or wire or glued with adhesive tape on a paper base or a polyethylene tape with a sticky layer, or covered with polypropylene tape according to the normative document. Sacks and bales with fish are firmly sewn. Bales with large fish can be tied with a rope or twine.
The cardboard bundles must be closed, the film bags are clamped or heat-sealed.
Other types of packaging may be used andPackages that meet the requirements of sanitation, standards and other NDs authorized by the state sanitary and epidemiological supervision for contact with the products and ensuring the safety and quality of the products during transportation and storage.
Freezing is an effective and long-term storage method.
The temperature in the thickness of the muscles in frozen fish is from -8 to -10 ° C and lower. To get high quality fish it is frozen
at -30 ° C (rapid freezing). With this freezing, the structure of the fish tissues is not disturbed.
The fish are frozen by natural cold (in the North), by ice and by salt mixtures (the temperature of melting of the mixture is -20 ° C), by an artificial method.
A common way of freezing in freezers. The duration of freezing is 4-5 days.
The most perfect way to freeze fish in freezers. The temperature inside the fish block reaches -18 ° C in 3-4 hours.
A method of freezing liquid nitrogen is used. The boiling point of nitrogen is -195.6 ° C. The process of freezing lasts 10-15 minutes.
To slow down the process of fat oxidation, shrinkage during storage, fish glaze with a thin layer of ice (2-3 mm), for this the blocks of fish are repeatedly immersed in cold water.
Instead of glazing, the fish is packed under vacuum into polymer films.
Ice-cream fish are classified by quality for I and II varieties except for small ones, which are not divided into varieties.
Fish of the first grade must have a clean surface, natural coloring, correct cutting. After thawing and cooking, check the smell and taste. They should be peculiar to this type of fish.
Second-class fish are allowed to break skin, broken gill cover, bruising, different fatness deviations from the correct cutting.
If the quality of the fish does not meet the requirements of Class II fish are considered non-standard.
Defects of frozen fish:presence of mold, unpleasant odor, flabbiness of the tissues, sour smell in the gills, rust, superficial yellowing of the fatty fish, drying of the outer layer and the formation of the spongy structure of the fish meat tissues, tarnishing of the surface.