Food commodities in general have properties susceptible to destroy (perisable). Likewise, fish, fish naturally contain nutritional parts such as fats, proteins, carbohydrates & water are highly preferred by microbes so that the fish is very simple destroyer was damaged when stored at room temperature.
A. System Quality Impairment
Immediately after the fish dies, there will be changes that lead to the occurrence of decay. The changes are primarily due to an enzyme activity, chemical & bacteria.
In general, fish are traded in a state already dead & are often in a state still alive. In the coursework of living conditions of fish can be traded in the long term. Conversely in the dead condition fish quality will soon decline.
Changes caused by the bacteria is triggered by the occurrence of destroy to the parts in fish by enzyme activity & chemical activity. Chemical activities to produce parts that are more simple. This condition is preferred bacteria that trigger the growth of bacteria in the body of the fish.
Enzymes contained in the fish body will change the body parts of fish & cause change in taste (flavor), smell (odor), visual (appearance) & texture (texture). Chemical activity is the occurrence of meat overweight oxidation by oxygen. Oxygen contained in air mengoksida fish & meat overweight smelly rancid (Rancid).
In fact, quality deterioration system was very complex. A crochet hook with each other, & work simultaneously. To prevent destroy quickly, it must always avoid the occurrence of the activities simultaneously.
B. Changes Following Fish Dead Fish
- Hyperaemia
Hyperaemia is the release of mucus from glands in the skin. The next system nodes forming a thick layer around the fish body. The release of mucus from the mucus glands, resulting from a typical reaction of an organism. Mucus consists of gluko protein & is a nice substrate for bacterial growth.
- Rigor mortis
As occurs in beef & other animal meat, this phase is marked by mengejangnya fish body after death. Spasm is due to the tools contained in the fish body is contracted because of chemical reactions that are influenced or controlled by the enzyme. In these circumstances, the fish is still said to be fresh.
- Autolysis
This phase occurs after the phase of rigor mortis. In this phase marked fish become weak again. Fish meat Lembeknya caused increased enzyme activity leading to an additional split fish meat to produce substances that are nice for bacterial growth.
- Bacterial decomposition (decomposition by bacteria)
In this phase the bacteria present in huge numbers at all, because of the earlier phase. This bacterial action at first very simultaneously as autolysis, & then run parallel.
The bacteria cause more destroy fish again, when compared with Autolisis.
Bacteria are microorganisms which are very small, only visible with a microscope a very powerful & can not be seen with the bare eye. The kinds of bacteria are: Pseudomonas, Proteus Achromobacter, Terratia, & Elostridium.
In the coursework of the fresh fish is still in a state, these bacteria do not interfere. However, if the dead fish, fish body temperature rises, resulting bacteria are immediately attacked. Imminent destruction of body tissues of fish, so that over time will change the composition of meat. Leading to a rotten fish. Body parts of fish that are often a target bacterial assault are:
* The whole body surface,
* The contents of the stomach,
* Gills.
Some things that cause the fish basically attacked by bacteria are as follows:
* Fresh fish & shellfish contain more liquid & less overweight, when compared with other types of meat. As a result more basically breed bacteria.
* The structure of fish & shellfish is not so ideal arrangement, compared to other types of meat. These conditions facilitate the occurrence of bacterial decomposition.
* After the events rigor, fresh fish & shellfish is simple to be alkaline or base. These conditions provide an appropriate surroundings for bacteria to breed.
Decrease the quality of fish can also occur by physical influences. Eg destroy by fishing gear when the fish are on deck, on board & for fish stored in the hold. Destroy suffered physically fish is due to poor handling. Causing injuries to the fish body & fish becomes soft.
C. Decrease the quality of fish by physical effects
* Fish are in the net long, for example in trawl nets, trawl withdrawal long. This condition may cause head or tail of a wound or broken.
* Pemakian ganco or shovel rough, so the wounded bodies of fish & fish can experience bleeding.
* Storage in the hold for long.
* Handling is clumsy when weeding, taking fish from nets, while entering the fish in the hold, & unload the fish from the hold.
* Meat fish will even be more apt to be flabby, when sunlight.
These can be caused by:
D. Factors Affecting Quality of Fish Decrease
How to Arrest
Fish caught with a trawl, pole, line, & so on would be better off when compared to those caught using the ill-net & long-line. This is because the first tools, the fish are caught immediately drawn on the deck, while on the tools that the fish are caught & left to die a very long time submerged in water. This condition causes the state of fish was not fresh when mounted on the deck.
Reaction of Fish Facing Death
Fish are moving speedy in his life, examples of cob, mackerel, shark, etc., usually fought hard when exposed to fishing gear. As a result, lots of lost power, speedy death, rigor mortis occurs faster & sooner ended. This condition causes the fish to rot quickly.
Unlike the pomfret fish, fish species is not much give a reaction to fishing gear, even sometimes they was still alive when mounted on the deck. So still have lots of energy savings. As a result, the elderly fish enter rigor mortis & long in this condition. This causes slow decomposition.
Type & Size of Fish
The speed of decay is different in each type of fish, because of differences in chemical composition of fish. Small fish decompose faster than larger fish.
Fish with weak physical condition, such as fish are sick, hungry or laying out much faster decay.
Physical Condition Before Death
Weather Situation
State of the hot air cloudy or rainy, lots of bumpy seas, accelerating decay.
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