Fish Processing
With a view to maintain the taste and quality of fish the process of transport, action, after care and preservation of fish after those are collected from the pond is called fish processing. Fish is rapidly decomposable creature.
The decomposition of fish starts at a definite time after collection and this extends rapidly. So the quality fish starts decreasing soon after their collection starting from the catching of the fish some time passes in bringing those to the market, selling and making those suitable for eating by the consumers. Fish may be decomposed and become unsuitable for consumption if these are not preserved at this time. So in order to control the quality of fish the activities. Starting from collection up to consumption like transportation, taking care and preservation should be done most carefully. There are several reasons for destroying the quality of fish or influencing the decomposition of fish. Such as
1. Keeping dead fish in unhygienic environment.
2. Not using ice for preservation of fish in low temperature after collection
3. Using unhygienic or polluted water for washing fish
4. Utilising uncleaned transport, using small amount of ice and having no knowledge about the use of ice.
5. Having no facilities for marketing including proper transportation.
In the context of present American food and medicine policy it has been asked to be more careful in the processing of fish and fish products. In this context if the processing facilities are improved, it will be possible to export 64000 metric tons within 2000 A.D. and from that it will be possible to earn foreign exchange of more than taka 2000 crore. It will play a vital role in strengthening economy of the courty.
One fourth of the total production of fish of fish of this country is Hilsa fish. Hilsa cought abundantly in a particular time of the year. Most of thess are decomposed for the want of processing. If these can be preserved properly more supply of protein in the country will be possible. So, in order to increase the standard of nutrition of the people and for economic development, the importance of fish and shrimp processing knows no bound.
The Reason for Fish Rottening In order to preserve fish it is important first to know the reason for fish rottening.
1. Bacterial attack.
2. Activities of enzymes
3. Chemical activities
There are numerous bacteria in the body of the fish. They can not do any harm if the fish is alive. But when the fish dies bacteria grow rapidly and cause changes in the body of the fish. As a result there starts rottening. There are different types of enzymes in the body of the fish. They are helpful for the fish when they are alive. But in dead fish the cells are broken by the activities of these enzymes and the fish starts tottening. The fish is composed of different chemical elements. After death of fish the activities of these chemical elements result in rottening of fish.
There are numerous bacteria in different parts like scales, gills, entrails etc. of the fish. After the death of the fish and these germs rapidly begin to act in the dead fish. As a result, fish begins to rot. Fish can be saved from decomposition if those are covered with abundant ice soon after catching. Preservation with ice is a good method if preservation is done temporarily or for short time. Although, freezing preserves fish and shrimps, drying or putting salt, initially those are to be preserved with ice. Fish are kept fresh with abundant ice up to 5-10 days in the local village markets. The temperature of fish become low when ice is used. As a result the bacteria or germs become, inactive. So fish are not decomposed easily. The portion of water in the fish remains intact when ice is used. For this reason fish remain fresh or lively.
Advantages of Fish Preservion with Ice-
1. Ice is relatively cheep
2. Easy to carry
3. Can cool fish rapidly
4. Does not cause any harm to the quality of fish.
5. Ice melting water clears the germs, blood things etc. those are stick to the body of the fish.
Generally in our country fish is transported in bamboo made basket or wooden box. In these cases firstly banana leaf or mat made of grass should be placed on the bottom of the basket and then one layer of ice is to be placed. Afterwards one layer of fish one layer ice is to be packed. In this way the basket is to be filled in with and ice. Lastly the basket will be tied with the help of banana leaves, coarse mat and Hessian so that sunlight cannot fall on the fish or the ice dose not melt quickly. The height of the basket should not be more than 40 cm. If the height is more than that, the fish may be flattened. If preserved with sufficient ice fish remains good up to 5-10 days.
After the basket or boxes full of package fish and shrimp arrive at the ware houses, those are separated from ice and the good ones are accepted. The accepted fish and shrimps are washed well with cold water.
In case of big fishes the entrails are brought out by tearing off the belly. The head and the fins are cut off and in cases of shrimps only the heads are separated. Then the shrimps are washed well in 20 PPM chlorine solution and primary grading is done on the basis of the size. These are again washed in pressed water having 10 PPM chlorine. At this stage these are weighed and graded for export, for example one grade may include 5 per pound, another grade may include 8-12 per pound, and other grade may contain 13-15 per pound and so on. After grading these are to be washed for the last time with 5 PM chlorine water and the shrimps are arranged as blocks on germ free polythene on a tray. This tray is called panning tray. After arranging the shrimps, the tray is filled with 3-5 PPM chlorine mixed cold. Water and it is made like a parcel covered by spread out polythene. Afterwards these panning trays are placed in specific chambers of plate freezer or blast freezer and refrigerated at 38o C to 40o C. At this temperature the shrimps are refrigerated in 2-3 hours.
One of such blocks weighs up to 1-2 kg. The panning trays are brought out of the freezer and the blocks are separated. Those are dipped into cold water mixed with 3-5 PPM chlorine. This process is called glazing. Glazing process accelerates dryness of fish and hinders decomposition. The glazed shrimps are packed with wax paper, placed in big cartoons and freezed at18o C. These frozen shrimps are exported in proper time.
In our country Hilsa is preserved only with salt. As there is excessive fat in Hilsa, they cannot be preserved by drying. In this case fish is preserved in two methods, such as:
1. Dry salting method
2. Solution salting method.
Firstly scales, blood, gills, entrails, eggs etc should be removed from the body of the fish. The fish should be cut crosswise into pieces so that they are not separated from each other. The ration of fish and salt should be 4:1. That is one kg salt should be used form a fish weighing 4 kg. During salting it should be noticed that enough salt enters into the cut parts. Making holes through the eyes of the fish should also push salt. After the fish is mixed with salt it should be kept in hips on a stand or bamboo mat spread over wooden platform. In arranging the layers of fish the heads and tails should be kept alternatively in same direction. If kept in this way after salting, Hilsa becomes fully salted within 15-20 days. Fish can be preserved up to 1 year after salting.
In case of small fishes, first of all those are washed well and dipped into salty water for some time. Those are picked up and water is allowed to ooze out. Then they are spread out on bamboo-made mat for sun drying. Fish becomes fully dried in 2-3 days in very hot sun. Dried fish is preserved in polythene bag.
In case of big fishes the scales, fins, entrails are removed and the fishes are washed well. Then the fishes are dissected vertically with the help of sharp knife. The dissected fish is kept dipped into saline water for sometime. Then those are picked up and hung longitudinally on a rack. By this water is allowed to ooze out and drying of fish starts. In this way the drying is completed within 5-7 days. The dried fish are kept in polythene bag and preserved in dry place.
The decomposition of fish starts at a definite time after collection and this extends rapidly. So the quality fish starts decreasing soon after their collection starting from the catching of the fish some time passes in bringing those to the market, selling and making those suitable for eating by the consumers. Fish may be decomposed and become unsuitable for consumption if these are not preserved at this time. So in order to control the quality of fish the activities. Starting from collection up to consumption like transportation, taking care and preservation should be done most carefully. There are several reasons for destroying the quality of fish or influencing the decomposition of fish. Such as
1. Keeping dead fish in unhygienic environment.
2. Not using ice for preservation of fish in low temperature after collection
3. Using unhygienic or polluted water for washing fish
4. Utilising uncleaned transport, using small amount of ice and having no knowledge about the use of ice.
5. Having no facilities for marketing including proper transportation.
Importance of Fish and Shrimp Processing
The role of fish and shrimp are very important in the economy of Bangladesh. In the export earning the contribution of fish and shrimp occupy the third position. During 2006-2007 financial year, Foreign exchange of 3352.89 crore taka was earned by exporting fish, shrimp and fishery products and these amount was about 5% of the total export earning. The production of fish and shrimp has increased as a result of taking proper steps and at the same time the demand for quality fish and shrimp has also been increasing gradually in and outside of the country. The lack of facilities for care after collection which was existing so long, has also been improved to a great extent in international market. This progress has been achieved as a result of improving the processing activities. If this vast potential resource is exported maintaining its quality in fact after proper processing, its demand will be incerased and on the other hand, the way of earning foreign exchange will also be expanded. As a result national economy will be enriched.In the fourth 5 year plan the target of fish production was 12 lakh ton and target for export was 28 thousand ton. The target of export profit was 971 crore taka. In the last year of the plan i.e. during 1994-95, almost one and a half time more profit than the targeted amount was earned by exporting fish and shrimp.In the context of present American food and medicine policy it has been asked to be more careful in the processing of fish and fish products. In this context if the processing facilities are improved, it will be possible to export 64000 metric tons within 2000 A.D. and from that it will be possible to earn foreign exchange of more than taka 2000 crore. It will play a vital role in strengthening economy of the courty.
One fourth of the total production of fish of fish of this country is Hilsa fish. Hilsa cought abundantly in a particular time of the year. Most of thess are decomposed for the want of processing. If these can be preserved properly more supply of protein in the country will be possible. So, in order to increase the standard of nutrition of the people and for economic development, the importance of fish and shrimp processing knows no bound.
The Reason for Fish Rottening In order to preserve fish it is important first to know the reason for fish rottening.
1. Bacterial attack.
2. Activities of enzymes
3. Chemical activities
There are numerous bacteria in the body of the fish. They can not do any harm if the fish is alive. But when the fish dies bacteria grow rapidly and cause changes in the body of the fish. As a result there starts rottening. There are different types of enzymes in the body of the fish. They are helpful for the fish when they are alive. But in dead fish the cells are broken by the activities of these enzymes and the fish starts tottening. The fish is composed of different chemical elements. After death of fish the activities of these chemical elements result in rottening of fish.
Symptoms of Rotted Fish
The colour of the body of a rotted fish and its gills become pale, the muscles become soft and loose, the eyes enter into holes and mucus appears in the gills.
The Preservation System of Fish and Shrimp
The preservation systems of fish and shrimp are as follows _ 1. Icing or chilling 2. Freezing 3. Drying 4. Salting1. Icing or Chilling
Fish and shrimp should be preserved to keep those good and to protect from decomposition, Fish and shrimp begin to rot if those are kept outside for long time. So fresh fish and shrimp are required for preservation. The preservation system of fish and shrimp is described below-There are numerous bacteria in different parts like scales, gills, entrails etc. of the fish. After the death of the fish and these germs rapidly begin to act in the dead fish. As a result, fish begins to rot. Fish can be saved from decomposition if those are covered with abundant ice soon after catching. Preservation with ice is a good method if preservation is done temporarily or for short time. Although, freezing preserves fish and shrimps, drying or putting salt, initially those are to be preserved with ice. Fish are kept fresh with abundant ice up to 5-10 days in the local village markets. The temperature of fish become low when ice is used. As a result the bacteria or germs become, inactive. So fish are not decomposed easily. The portion of water in the fish remains intact when ice is used. For this reason fish remain fresh or lively.
Advantages of Fish Preservion with Ice-
1. Ice is relatively cheep
2. Easy to carry
3. Can cool fish rapidly
4. Does not cause any harm to the quality of fish.
5. Ice melting water clears the germs, blood things etc. those are stick to the body of the fish.
Method of Icing
Generally in our country fish is transported in bamboo made basket or wooden box. In these cases firstly banana leaf or mat made of grass should be placed on the bottom of the basket and then one layer of ice is to be placed. Afterwards one layer of fish one layer ice is to be packed. In this way the basket is to be filled in with and ice. Lastly the basket will be tied with the help of banana leaves, coarse mat and Hessian so that sunlight cannot fall on the fish or the ice dose not melt quickly. The height of the basket should not be more than 40 cm. If the height is more than that, the fish may be flattened. If preserved with sufficient ice fish remains good up to 5-10 days.2. Fish and Shrimp Preservation by Freezing
The process of preservation of dish and shrimp by lowering down their body temperature of is called freezing. By freezing the liquid between cell and tissue is converted into ice. This is a very popular method of fish and shrimp preservation. In this method shrimps can be preserved up to 1 year maintaining all the qualities of fish. In Bangladesh, mainly shrimps, frog legs, lobsters and all are exported after preserving by freezing. Mainly air blast freezer and plate freezer are used for refrigeration.After the basket or boxes full of package fish and shrimp arrive at the ware houses, those are separated from ice and the good ones are accepted. The accepted fish and shrimps are washed well with cold water.
In case of big fishes the entrails are brought out by tearing off the belly. The head and the fins are cut off and in cases of shrimps only the heads are separated. Then the shrimps are washed well in 20 PPM chlorine solution and primary grading is done on the basis of the size. These are again washed in pressed water having 10 PPM chlorine. At this stage these are weighed and graded for export, for example one grade may include 5 per pound, another grade may include 8-12 per pound, and other grade may contain 13-15 per pound and so on. After grading these are to be washed for the last time with 5 PM chlorine water and the shrimps are arranged as blocks on germ free polythene on a tray. This tray is called panning tray. After arranging the shrimps, the tray is filled with 3-5 PPM chlorine mixed cold. Water and it is made like a parcel covered by spread out polythene. Afterwards these panning trays are placed in specific chambers of plate freezer or blast freezer and refrigerated at 38o C to 40o C. At this temperature the shrimps are refrigerated in 2-3 hours.
One of such blocks weighs up to 1-2 kg. The panning trays are brought out of the freezer and the blocks are separated. Those are dipped into cold water mixed with 3-5 PPM chlorine. This process is called glazing. Glazing process accelerates dryness of fish and hinders decomposition. The glazed shrimps are packed with wax paper, placed in big cartoons and freezed at18o C. These frozen shrimps are exported in proper time.
Fish Preservation by Salting
Salt absorbs water from the body of fish. By way of this the amount of water from the body of fish is decreased to such level that the activities of the bacteria living in the body of the fish stop. As a result fish is not decomposed. By processing in this method fish can be preserved unto 1 year.In our country Hilsa is preserved only with salt. As there is excessive fat in Hilsa, they cannot be preserved by drying. In this case fish is preserved in two methods, such as:
1. Dry salting method
2. Solution salting method.
Dry Salting Method
Firstly scales, blood, gills, entrails, eggs etc should be removed from the body of the fish. The fish should be cut crosswise into pieces so that they are not separated from each other. The ration of fish and salt should be 4:1. That is one kg salt should be used form a fish weighing 4 kg. During salting it should be noticed that enough salt enters into the cut parts. Making holes through the eyes of the fish should also push salt. After the fish is mixed with salt it should be kept in hips on a stand or bamboo mat spread over wooden platform. In arranging the layers of fish the heads and tails should be kept alternatively in same direction. If kept in this way after salting, Hilsa becomes fully salted within 15-20 days. Fish can be preserved up to 1 year after salting.4. Fish Drying
The process of preserving fish by removing water from the body of fish by sun heat is called fish drying. Excepting the fatty fishes, drying process can preserve all fishes big or small.In case of small fishes, first of all those are washed well and dipped into salty water for some time. Those are picked up and water is allowed to ooze out. Then they are spread out on bamboo-made mat for sun drying. Fish becomes fully dried in 2-3 days in very hot sun. Dried fish is preserved in polythene bag.
In case of big fishes the scales, fins, entrails are removed and the fishes are washed well. Then the fishes are dissected vertically with the help of sharp knife. The dissected fish is kept dipped into saline water for sometime. Then those are picked up and hung longitudinally on a rack. By this water is allowed to ooze out and drying of fish starts. In this way the drying is completed within 5-7 days. The dried fish are kept in polythene bag and preserved in dry place.
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