Nature of water to be used in ice
· Clean and Contamination free water should be used for the manufacture of ice
· Municipal Water shouid not be used directly in ice production.It can be used after necessary cleaning and chlorining (5-10 ppm)
· Water from ponds,lakes,ditches,rivers,canals,or seashore should not be used.These natural waters contain mud ,dirt,debris,bacteria,and others contaminants that,if used in ice,may serve as a basic of fresh contamination in fish and lead to quick spoilage;
· Sea water contains salt and transformed into ice at much lower temperature than the usal temperature required in ice formation.Therefore,the quality of ice from sea water is not good.To form ice,sea water requires longer time and more electricity.However,seawater is sometimes used in ice production if freshwater is scare ,as in case of big trawler or factory shin in the sea or in desert states.
· Quality of ice will be good if adequitly treated tubewell or deep tubewell water is used.
· Large tanks reservoirs where water is preserved in ice plant should be cleaned regularly;
· Antibiotics in water prescribed dose may increase shelf life of ice fish but this should strictly follow local and international regulation.
Approprite method of icing
Generally,icing of fish is done in 3 stages:
I. On board fishing vessel after harvest
II. After landing or before transportation
III. During retail sale
Icing On board fishing vessel after harvest
Use of ice on board fishing vessels is a common practice in commercial fisheries where trips are on several days duration and fish must be kept in good condition until landing.In our country ,in small artisanal boats which are engaged in daily fishing ,it is not practicable to construct fish hold ,because the boats are too small to provide space.However,icing must be done in fish In all types of fishing boats including motorized or non motorized daily fishing boats.To minimize space problem ,small boats can use ice box on the deck.The size of ice box may be determined on the basis of the size of the catch.In such case where the fishermen is at sea for pnly a short time and can not carry ice ,icing shold be done at soon as the fish lands. Mechnized fishing boats which store their catch on ice have three fish holds beneath the working deck. These fish rooms are use to carry and keep ice and fish.
The fish hold in the fishing boat must be-
ü So designed that is easy to clean and keep clean Hard and smooth surfaced ,free from cracks and crev;ices which could harbour dirt and bacteria;
ü Strong and corrosion resistant;
ü Robust and able to withstand blows inflicted by ice axes ,shovels and pound boards.etc;
ü Well insulated and watertight;
ü Light in color and light in weight ;
ü Must not contaminate fish ;
ü Must not be corroded by fish oil ,ammonia,brine etc;
ü Must have adequate drainage to drain out ice melt water.
Icing method on board vessel
Fish is stored on board vessel by 3 types:
A. Bulking:practiced in small engine boarts;
B. Shelving:limited use in trallers and
C. Boxing:popular in trallersand mechanized boats
Generally,fish are bulk iced in the fish hold of the motorized
Artisanal fishing boats.The sized of fish hold depends on the size of boat.Generally ,it varies from 10-8 feet with a depth of 4-5 feetin 18 HP engine boats to 12.5-10 feet with with a depth of 6-7 feet in 65
SL
Disadvantages of bulk icing
Advantages of icing fish in box
01
Due to pressure of fish and ice from the top ,fish at the bottom are rapidly deteriorated
No such high pressure exerted on to the bottom fish at the depth of box in small
02
Due to bulk content adequate handling is not possible
Fish can be adequately hadle iced or transferred separately
03
Excess labour is required for movig and handling fish
Minimum labour is required for handling boxes
04
Fish of different species ,size and qualities are mixed togather that may pose certain species vernerable to spoilage
Fish of different species ,size and qualities can be kept in icedseperately
05
Icing is not proper
Adequate and appropriate icing can be done
06
Skill of fishermen is not improved
Fishermen can improve skills in fish handling
HP engine boats.Fish are stock piled with ice in such a big room.Sometimes this big room is divided into section using pound boats supported by stancions.Beause the pressure of huge quantitaty of fish and ice from the top,the fish at the bottom of the fish hold are deteriorated rapidly,although they are kept insufficient ice.Beside it is extremely difficult to handle and take care of such huse quantity of fish.Most of the times different species and quantities of fish are stock filed togather.This also deteriored the quality of fish.
Adequate fish hold temperature
Ice has yhe capacity to insulale as well as chill fish.However,fish can also be properly chilled the ice can melt and cold melt-water can tricle around the fish to absorbthe heat of the fish.If the fish is so cold that the ice can not melt,pocketsof the heat around the fish will from and cause rapid spoilage.
The ideal fish hold temperature is 0-1 centigrate enough above freezing to allow some melting but cold enough to maintain quality.Fish must be protected from the heat coming into the fish room from out side as well.Poor insulation in the fish hold can be compensated by using extra ice against the walls as added insulation.
Fish is properly iced in fish hold
· Finely crused ,clean ice is used to speed up cooling while minimizing bruising of fish.
· All areas in the fish room where heat penetrates are given extra heavy layers of ice
· Fish are stowed evenly to avoid cluping while allowing even distribution of fish and ice
· Not too much fish is stowed vertically in the fish room ,room section ,pen ,drum or box so that the pressure of fish from above can not damage the fish kept in bottom.
· There is a substantial amount of ice evenly mixed with fihsh at discharge and the fish at discharge at 0-1 centegrate
· The ratio of fish to ice is 1:1 in the winter and summer.
Icing fish and landing and transportation
Fish still needs tobe chilled after landing ,whethereit is destined for different processing in chilled room or for marketing wet fish.Icing can quickly reduce the temperature with in several hours whereas fish kept in a chilled room may take several days.
In Bangladesh ,urban areas take daily deliveries of fresh fish from fish landing center ,those are generally mamy hundreds of kilometers away.Fish are generally packed with ice in bamboo basket or gunny sacks wrapped by polythenesheets or mat made of plant leaves,locally called Hogla,with negligible insulation;they are loaded into open tracks or freight wagons on passengers trainingand may spend up to 1-2 days in transit .Sides and bottom of the fish hold on the truck are covered with plain polythene sheet.A layer of Hogla is sometimes used the bottom.Fish are bulked packet with alternate ice layer in the truck and transported with top surface covered by polythene sheet and course tent.Under this circumanstences ,melting of ice is very high and re icing during transport necessary.But reicing during transportation is not need.
Approprite ice box for preparation
Ø Insulaled ice box of 45 cm deep in an ideal container.For fatty Hilisha ,it should be less than 20 cm deep.
Ø It is not had to used plastic box to transport iced fish.Plastic box to transport iced fish.Plastic box can be insulaled by covering with a lid and placing stayrofoam in between two layers of walls,bottom and top.
Ø Aluminium container with a lid can also be used to carry ice fish locally.
Ø Outlet at the bottom of the ice box to drain out melted water is a must.
Low cost ice box
Several methods have been developed to transport to preserved fish effectively in rural areas in Bangladesh.Some of the methods have been successfully used by the field level fishermen,fish traders ,small scale fish processor and transporters in the coastal region and freshwater landing centers.Construction such a lowcost but effective ice box that is being used by small scale fish traders of the country is given below:
I. Bamboo basket presently used in wet fish transportation throughout the country is transformed into insulated ice box very simply. In such modified basket fish can not come in contract of the wall of the basket ,since it is wrapped all along with polythene gunny sacs and plain polythene sheet.Thus there is no change of contamination of fish from the split bamboo that generally harbours bacteria and contamitants.it is easy to clean and keep clean too.
II. To make a cost ice box,take a fine woven split bamboo basket of 25-30 kg capacity.Wrap inside the basket with one layer polythene gunny sacs in such a way that the extended portion of the sac remain beyond the upper edge of the basket.Place an adequate size of mat of plant leaves,Hogla in side the basket to cover the area inside.Put another layer of equal size polythene sac on Hogla layer and stitch these three layers of wrapping materials with lylone twine of the basket so that all wrapping materials remain fixed with the basket.
III. Now,to ice fish in the basket ,place a plain polythene sheet or a polythene sac inside the wrapped basket .This polythene sheet can be washed and reused after each operation.Place ice and fish alternately in adequate fashion in the polythene sac of the basket sothat an ideal icing condition is maintained.Use extra layer of ice on the top of fish.Insert a small plastic pipe through the bottom of the basket to pass out melted water .Keep the pipe finely tightened with the basket and wrapping materials in the bottom sothat it is not misplaced during handling and transporting and melting water can not leak out through the outside wall of the pipe.Finally ,wrap the extended portions of all wraping materials at the top of the basket.The basket is now ready t preserve and transport ice fish.
IV. Transportation of iced fish in traditional baskets creates a problem with a melted water.In this modified basket ,a two feet long plastic pipe in inserted through a hole at the bottom of the basket to drain out water.The rear end of the pipe is tightened with the top edge of the basket.Where the rear end of the pipe is down at regular intervals during the initial stage of icing,melted water is pass out easily.Adequately iced fish in such modified ice box can be kept in good quality for 24 hours without adding new ice .Fish can be keot well for 6-7 days if small amount of craused ice is added very after 24 hours at the top of fish.Hogla leaves can serve as good insulating material.Total cost Incurred for such a modified basket is TK.60-70.Such an ice box can carry 20-25 kg of iced iced fish and can be used for more than a year.
Plastic container modified into ice box
Beside ,little bit expensive for the poor fishermen ,another effective icing device introduced into coastal region can used through out the country .For commercial transportation of fish this ice box has been proved to be very fruitful.A similar type of plastic containers,which are now being used in shrimp processing plants for various purpose ,can be used in outside transportation and preservation of iced fish after necessary modification.The side wall of the container should be double layer all along including bottom ,and the top ,keeping 2.5-3.0 cm space between the two layers.A screw tap is insulated at the based of one side wallto drain out melted water.Efficacy of these modified plastic container as ice box has been tested and found very good result .This type of plastic ice box can be manufactured by any ordinary plastic factory .Commercial fish traders can use this type of light and durable ice box extensively to transport wet fish through tracks ,ships and other vehicles.
Method of icng fish market
§ Use ice block prepared from clean and contamination free water
§ Use clean pound box and pestle to crush block ice ,crush ice into small ice
§ If necessary,gut larger fish and wash all fish with sufficient clean water
§ Put a layer of ice at the bottom of the box before filling,put ice layers on either sides and layer on the top of the fish
§ Stow fish at even and alternate fish and ice layer
§ Keep sufficient ice around the fish
§ Fllow a fish to ice ratio of 1:2 in hotter months and 1:1 in December to February
Icing fish in fish market
Ø Keep fish in ice in covered ice box all day long,even during sale.
Ø Keep excess or left over fish in community ice box for next day sale.
Deposit extra ice in community ice box.If necessary ,operete community ice box through community based approsed.
· Clean and Contamination free water should be used for the manufacture of ice
· Municipal Water shouid not be used directly in ice production.It can be used after necessary cleaning and chlorining (5-10 ppm)
· Water from ponds,lakes,ditches,rivers,canals,or seashore should not be used.These natural waters contain mud ,dirt,debris,bacteria,and others contaminants that,if used in ice,may serve as a basic of fresh contamination in fish and lead to quick spoilage;
· Sea water contains salt and transformed into ice at much lower temperature than the usal temperature required in ice formation.Therefore,the quality of ice from sea water is not good.To form ice,sea water requires longer time and more electricity.However,seawater is sometimes used in ice production if freshwater is scare ,as in case of big trawler or factory shin in the sea or in desert states.
· Quality of ice will be good if adequitly treated tubewell or deep tubewell water is used.
· Large tanks reservoirs where water is preserved in ice plant should be cleaned regularly;
· Antibiotics in water prescribed dose may increase shelf life of ice fish but this should strictly follow local and international regulation.
Approprite method of icing
Generally,icing of fish is done in 3 stages:
I. On board fishing vessel after harvest
II. After landing or before transportation
III. During retail sale
Icing On board fishing vessel after harvest
Use of ice on board fishing vessels is a common practice in commercial fisheries where trips are on several days duration and fish must be kept in good condition until landing.In our country ,in small artisanal boats which are engaged in daily fishing ,it is not practicable to construct fish hold ,because the boats are too small to provide space.However,icing must be done in fish In all types of fishing boats including motorized or non motorized daily fishing boats.To minimize space problem ,small boats can use ice box on the deck.The size of ice box may be determined on the basis of the size of the catch.In such case where the fishermen is at sea for pnly a short time and can not carry ice ,icing shold be done at soon as the fish lands. Mechnized fishing boats which store their catch on ice have three fish holds beneath the working deck. These fish rooms are use to carry and keep ice and fish.
The fish hold in the fishing boat must be-
ü So designed that is easy to clean and keep clean Hard and smooth surfaced ,free from cracks and crev;ices which could harbour dirt and bacteria;
ü Strong and corrosion resistant;
ü Robust and able to withstand blows inflicted by ice axes ,shovels and pound boards.etc;
ü Well insulated and watertight;
ü Light in color and light in weight ;
ü Must not contaminate fish ;
ü Must not be corroded by fish oil ,ammonia,brine etc;
ü Must have adequate drainage to drain out ice melt water.
Icing method on board vessel
Fish is stored on board vessel by 3 types:
A. Bulking:practiced in small engine boarts;
B. Shelving:limited use in trallers and
C. Boxing:popular in trallersand mechanized boats
Generally,fish are bulk iced in the fish hold of the motorized
Artisanal fishing boats.The sized of fish hold depends on the size of boat.Generally ,it varies from 10-8 feet with a depth of 4-5 feetin 18 HP engine boats to 12.5-10 feet with with a depth of 6-7 feet in 65
SL
Disadvantages of bulk icing
Advantages of icing fish in box
01
Due to pressure of fish and ice from the top ,fish at the bottom are rapidly deteriorated
No such high pressure exerted on to the bottom fish at the depth of box in small
02
Due to bulk content adequate handling is not possible
Fish can be adequately hadle iced or transferred separately
03
Excess labour is required for movig and handling fish
Minimum labour is required for handling boxes
04
Fish of different species ,size and qualities are mixed togather that may pose certain species vernerable to spoilage
Fish of different species ,size and qualities can be kept in icedseperately
05
Icing is not proper
Adequate and appropriate icing can be done
06
Skill of fishermen is not improved
Fishermen can improve skills in fish handling
HP engine boats.Fish are stock piled with ice in such a big room.Sometimes this big room is divided into section using pound boats supported by stancions.Beause the pressure of huge quantitaty of fish and ice from the top,the fish at the bottom of the fish hold are deteriorated rapidly,although they are kept insufficient ice.Beside it is extremely difficult to handle and take care of such huse quantity of fish.Most of the times different species and quantities of fish are stock filed togather.This also deteriored the quality of fish.
Adequate fish hold temperature
Ice has yhe capacity to insulale as well as chill fish.However,fish can also be properly chilled the ice can melt and cold melt-water can tricle around the fish to absorbthe heat of the fish.If the fish is so cold that the ice can not melt,pocketsof the heat around the fish will from and cause rapid spoilage.
The ideal fish hold temperature is 0-1 centigrate enough above freezing to allow some melting but cold enough to maintain quality.Fish must be protected from the heat coming into the fish room from out side as well.Poor insulation in the fish hold can be compensated by using extra ice against the walls as added insulation.
Fish is properly iced in fish hold
· Finely crused ,clean ice is used to speed up cooling while minimizing bruising of fish.
· All areas in the fish room where heat penetrates are given extra heavy layers of ice
· Fish are stowed evenly to avoid cluping while allowing even distribution of fish and ice
· Not too much fish is stowed vertically in the fish room ,room section ,pen ,drum or box so that the pressure of fish from above can not damage the fish kept in bottom.
· There is a substantial amount of ice evenly mixed with fihsh at discharge and the fish at discharge at 0-1 centegrate
· The ratio of fish to ice is 1:1 in the winter and summer.
Icing fish and landing and transportation
Fish still needs tobe chilled after landing ,whethereit is destined for different processing in chilled room or for marketing wet fish.Icing can quickly reduce the temperature with in several hours whereas fish kept in a chilled room may take several days.
In Bangladesh ,urban areas take daily deliveries of fresh fish from fish landing center ,those are generally mamy hundreds of kilometers away.Fish are generally packed with ice in bamboo basket or gunny sacks wrapped by polythenesheets or mat made of plant leaves,locally called Hogla,with negligible insulation;they are loaded into open tracks or freight wagons on passengers trainingand may spend up to 1-2 days in transit .Sides and bottom of the fish hold on the truck are covered with plain polythene sheet.A layer of Hogla is sometimes used the bottom.Fish are bulked packet with alternate ice layer in the truck and transported with top surface covered by polythene sheet and course tent.Under this circumanstences ,melting of ice is very high and re icing during transport necessary.But reicing during transportation is not need.
Approprite ice box for preparation
Ø Insulaled ice box of 45 cm deep in an ideal container.For fatty Hilisha ,it should be less than 20 cm deep.
Ø It is not had to used plastic box to transport iced fish.Plastic box to transport iced fish.Plastic box can be insulaled by covering with a lid and placing stayrofoam in between two layers of walls,bottom and top.
Ø Aluminium container with a lid can also be used to carry ice fish locally.
Ø Outlet at the bottom of the ice box to drain out melted water is a must.
Low cost ice box
Several methods have been developed to transport to preserved fish effectively in rural areas in Bangladesh.Some of the methods have been successfully used by the field level fishermen,fish traders ,small scale fish processor and transporters in the coastal region and freshwater landing centers.Construction such a lowcost but effective ice box that is being used by small scale fish traders of the country is given below:
I. Bamboo basket presently used in wet fish transportation throughout the country is transformed into insulated ice box very simply. In such modified basket fish can not come in contract of the wall of the basket ,since it is wrapped all along with polythene gunny sacs and plain polythene sheet.Thus there is no change of contamination of fish from the split bamboo that generally harbours bacteria and contamitants.it is easy to clean and keep clean too.
II. To make a cost ice box,take a fine woven split bamboo basket of 25-30 kg capacity.Wrap inside the basket with one layer polythene gunny sacs in such a way that the extended portion of the sac remain beyond the upper edge of the basket.Place an adequate size of mat of plant leaves,Hogla in side the basket to cover the area inside.Put another layer of equal size polythene sac on Hogla layer and stitch these three layers of wrapping materials with lylone twine of the basket so that all wrapping materials remain fixed with the basket.
III. Now,to ice fish in the basket ,place a plain polythene sheet or a polythene sac inside the wrapped basket .This polythene sheet can be washed and reused after each operation.Place ice and fish alternately in adequate fashion in the polythene sac of the basket sothat an ideal icing condition is maintained.Use extra layer of ice on the top of fish.Insert a small plastic pipe through the bottom of the basket to pass out melted water .Keep the pipe finely tightened with the basket and wrapping materials in the bottom sothat it is not misplaced during handling and transporting and melting water can not leak out through the outside wall of the pipe.Finally ,wrap the extended portions of all wraping materials at the top of the basket.The basket is now ready t preserve and transport ice fish.
IV. Transportation of iced fish in traditional baskets creates a problem with a melted water.In this modified basket ,a two feet long plastic pipe in inserted through a hole at the bottom of the basket to drain out water.The rear end of the pipe is tightened with the top edge of the basket.Where the rear end of the pipe is down at regular intervals during the initial stage of icing,melted water is pass out easily.Adequately iced fish in such modified ice box can be kept in good quality for 24 hours without adding new ice .Fish can be keot well for 6-7 days if small amount of craused ice is added very after 24 hours at the top of fish.Hogla leaves can serve as good insulating material.Total cost Incurred for such a modified basket is TK.60-70.Such an ice box can carry 20-25 kg of iced iced fish and can be used for more than a year.
Plastic container modified into ice box
Beside ,little bit expensive for the poor fishermen ,another effective icing device introduced into coastal region can used through out the country .For commercial transportation of fish this ice box has been proved to be very fruitful.A similar type of plastic containers,which are now being used in shrimp processing plants for various purpose ,can be used in outside transportation and preservation of iced fish after necessary modification.The side wall of the container should be double layer all along including bottom ,and the top ,keeping 2.5-3.0 cm space between the two layers.A screw tap is insulated at the based of one side wallto drain out melted water.Efficacy of these modified plastic container as ice box has been tested and found very good result .This type of plastic ice box can be manufactured by any ordinary plastic factory .Commercial fish traders can use this type of light and durable ice box extensively to transport wet fish through tracks ,ships and other vehicles.
Method of icng fish market
§ Use ice block prepared from clean and contamination free water
§ Use clean pound box and pestle to crush block ice ,crush ice into small ice
§ If necessary,gut larger fish and wash all fish with sufficient clean water
§ Put a layer of ice at the bottom of the box before filling,put ice layers on either sides and layer on the top of the fish
§ Stow fish at even and alternate fish and ice layer
§ Keep sufficient ice around the fish
§ Fllow a fish to ice ratio of 1:2 in hotter months and 1:1 in December to February
Icing fish in fish market
Ø Keep fish in ice in covered ice box all day long,even during sale.
Ø Keep excess or left over fish in community ice box for next day sale.
Deposit extra ice in community ice box.If necessary ,operete community ice box through community based approsed.