Grade III. This consists of fish which failed to meet the requirements of Grades I and II, but which has the following
LET US STUDY Let us define
Autolysis - the self digestion of the fish due to enzymes naturally present in the digestive tract of the fish resulting to partial liquefaction and softening of the fish flesh.
Contaminant - a substance that makes other substances like air, water, or food impure. They include germs and microorganisms that infect the food.
Contamination - a state of being infected with germs or microorganisms or made impure with contaminants.
Curing solution - a mixture of salt and water which is used to cure or treat fish.
Drying - a method of curing in which moisture is removed through natural or artificial means. Drying involves exposure to natural air currents and humidity is regulated by climatic condition. Artificial drying or dehydration involves the use of a mechanical device which controls relative humidity as in the use of oven, kiln or dehydrator.
Dry salted fish - a fishery product which is dried first before it is salted as in dry salting of alamang or small shrimp.
Fermenting - a method suitable for small fishes with fish paste (bagoong) and fish sauce (patis) as end products.
Fish Curing - a method of preserving fish and other fishery products by means of salting, drying and dehydration, smoking and pickling.
Isthmus - the part that joins the lower jaw of the mouth of a fish and the breast which is located at the lower end of the operculum.
Kench salted fish - refers to a heavily salted fish locally known as binuro.
Osmosis - the process whereby moisture from the fish is removed while salt enters it through the skin as semi – permeable membrane.
Pellicle - a glossy film substance imparted to the fish that aids in giving the fish desirable smoke color.
Plasmolysis - the shrinking of the protoplasm of a living cell like a bacterial cell due to the loss of water by osmosis.
Salting - a curing fish which is integrated in almost all methods of preserving fish with salt as the chief preservative.
Smoking - a smoke – curing method of preserving fish by the application of smoke with the aid of salting, drying and heat treatment.
Submerge - means to place under water or cover with water.
In developing countries like the Philippines, fish curing is still the principal method of processing fish and other fishery products. Many fish processors prefer to engage in producing cured fishery products like salted fish (binuro, tinabal, guinamos and bagoong), smoked fish (tinapa) and dried fish in whole form like the dried small fishes (dilis and slipmouth) and the dried splitted fish (daeng) because most Filipinos prefer to eat these products rather than the canned, iced or frozen ones.
In preparing cured fishery products, the methods used are salting, smoking, drying and dehydration.
Procedure in Curing Fish A. Salting
Salting is one of the fish curing methods wherein salt is the chief preservative. It preserves fish by lowering its moisture content through the process of osmosis. During osmosis, the bacterial cells undergo plasmolysis as a result of osmotic pressure thus destroying the bacteria.
Salt – The Chief Preservative in Curing Fish through Salting and Smoking There are five methods of salting fish as follows:
1. Kench or Dry salting involves heavily salting the fish with dried salt granules with a ratio of 1:7 ( 1 part fish to 7 parts salt). The salted product prepared through this method is referred to as binuro.
The species of fish commonly kench-salted are:
1. Indian sardine (tamban tuloy) 2. Fimbriated herring (tunsoy)
3. Short – bodied mackerel (hasa – hasa) 4. Striped mackerel (alumahan)
5. Yellow – striped crevalle (salay – salay)
Procedure:
a. Weigh the fish
b. Eviscerate and wash them with fresh water. The scales may or may not be removed.
c. Soak in a 10% brine, (1 part salt to 9 parts water), for 30 minutes to leach out the blood.
d. Half dry the fish for two hours.
e. Salt them with the ratio of 1:7 (1 part fish to 7 parts salt) by weight.
Concrete Tank for Brine - Salting of Fish
f. Pack the fish in newspaper for home consumption and pack in wooden boxes for commercial purposes.
Wooden Boxes for Packing Cured Fish
2. Dry salting. In this method, the fishery product is dried first before it is salted as in dry salting of alamang (small shrimps) or anchovies.
Also, fresh small herrings are dried first before they are salted.
The steps in preparing salted alamang are as follows:
a. Remove the adhering foreign materials from small shrimps.
b. Wash then dry the small shrimps under the sun for one day.
c. Pound the dried small shrimps with the use of mortar and pestle.
d. Add salt to pounded shrimps. The ratio is 1:5 (1 part salt to 5 parts pound shrimps).
e. Add little washed sugar to salted pounded shrimps. The ratio is 1:32 (1 part washed sugar to 32 parts salted pounded shrimps). Blend them thoroughly.
f. After mixing, form them into paste ready for sale.
3. Dry salting to make brine. It involves curing the fish with dry salt granules before they are packed in containers so that brine will be allowed to form. The product prepared through this method is known locally by the Cebuanos as tinabal. The species of fish commonly cured through dry salting to make brine are short-bodied mackerel, striped mackerel, yellow striped crevalle and yellow tuna or albacora.
The steps in salting fish through dry salting to make brine are as follows:
a. Weigh the fish
b. Eviscerate them and if their flesh are thick, make a gash on them.
c. Wash them with freshwater and pack in 10% brine for 30 minutes to leach out the blood.
d. Drain the fish for one hour.
e. Rub thoroughly each fish with salt so that all surfaces will be coated.
f. Pack the fish in layers in big plastic or glass containers with salt sprinkled between layers so that brine formed will cover the fish. The ratio of salt to fish is 1:4 (1 part salt to 4 parts fish) or 20% by weight. Pack also the fish in 25% brine with the ratio of 1:3 (1part salt to 3 parts fish) by weight.
4. Brine salting is curing the fish with the brine formed after letting the mixture of salt and fish stand for 24 hours. The product produced through this method is locally known as ginamos by the Cebuanos.
The brine salted fish are stored for one month or two months and usually eaten uncooked with calamansi juice or vinegar. The brine of this salted product is called una, which is used as seasoning for broth and vegetables. Fish commonly brine - salted are anchovy and herring.
The steps in brining the fish are as follows:
a. Weigh the fish and wash them in fresh water.
b. Mix salt with the fish in a proportion of 1:4 or 1:5 by weight.
c. Let the mixture stand for 24 hours.
d. Decant the brine formed.
e. Boil the brine formed together with the saturated brine for 30 minutes and let it cool.
f. Pack the salted fish in big plastic or glass container.
g. Pour the boiled brine into the salted fish.
h. Cover the container and store in a cool place.
5. Fermenting is a method of salting fish which is done by dry salting the fish and left to ferment so that protein hydrolyzes to produce paste and sauce. This method has two products, namely fish paste or bagoong and fish sauce or patis.
Some fish processors apply papain to make the fermentation period shorter and faster. Anchovy, sardine, herring, shad, silverside and slipmouth are common species fermented.
The steps in fermenting fish are as follows:
a. Weigh the fish.
b. Cut into small pieces if fish are large.
c. Wash the fish and drain for 30 minutes.
d. Mix salt thoroughly with the fish in a ratio of 1:4 (1 part salt to 4 parts fish) by weight or 20%. If 25% is used, the ratio is 1:3 (1 part salt to 3 parts fish) by weight.
e. Add papain to shorten the fermentation period (optional).
f. Pack the fish in plastic or glass containers.
g. Store the fermented fish for a month to a year for it to develop the aroma caused by the breakdown of fish proteins.
h. Separate the fish sauce from the fish paste.
i. Extract the fish sauce and pack in bottles.
Containers for Fermenting Fish
B. Smoking
Smoking or smoke-curing is a method of preserving fish by the application of smoke with the aid of salting, drying and heat treatment.
Smoked fish is locally known as tinapa. The two types of smoking are hot smoking and cold smoking.
Hot smoking is a slow type of broiling wherein fish is placed near the fire at smoke temperatures ranging from 66˚C to 88˚C. Smoking lasts for one hour to 3 hours depending upon the size of the fish. The fish are cooked in addition to being saturated with smoke. This is also referred to as barbecue smoking. There are two hot smoking methods namely:
1. boiling
2. pressure cooking
Below are some types of not smoke house for not smoking:
Native Pot Type Drum Type
Cold smoking is done by placing the fish far away from the fish at a distance of almost two meters away from the source of smoke with a temperature ranging from 32˚C to 43˚C. Below are examples of Smokehouse used in cold smoking:
Cabinet Type Smokehouse
Differences Between Hot Smoking and Cold Smoking
Differences Hot Smoking Cold Smoking 1. Distance of fish
from source of heat Close proximity to the
fire 2 meters away from
the source of fire 2. Temperature 66˚C to 88˚C 32˚C to 43˚C 3. Length of smoking 1 – 3 hours 1 to 2 weeks 4. Finished product Little bit moist and
heavier in weight Dry and lighter in weight
5. Shelf - life 3 days to a week More than a month
Procedure in Hot Smoking Fish Boiling Method of Hot Smoking
a. Weigh the fish and wash them with freshwater.
b. Remove the internal organs by ripping out the gills, making sure the isthmus is not destroyed. The removal of viscera eradicates the enzymes that cause autolysis and reduces the microorganisms present.
c. Rewash the fish with freshwater.
d. Soak the fish in saturated brine for two hours.
e. Boil the fish in 10% brine solution for 10 minutes till the eyes of fish become white.
f. Dry the boiled fish in a cool, shady and breezy place for 1 to 3 hours or until a thin slimy skin or pellicle is formed on the surface.
g. Hot-smoke the fish at temperatures ranging from 66OC to 88OC for 1 to 3 hours depending upon the size of the fish.
Pressure-Cooking of Hot Smoking
a. Weigh the fish and wash with freshwater.
b. Remove the viscera by ripping out gills through the operculum. The removal of viscera leads to the destruction of enzymes and reduction of microorganisms present in the fish. Be sure the isthmus is not destroyed.
c. Rewash the fish with freshwater.
d. Soak the fish in saturated brine solution for two hours.
e. Pressure- cook the fish at temperature of 240OF or 10 pounds, pressure per square inch gauge for 90 minutes for milkfish; 70 minutes for short-bodied and striped mackerel;
and 60 minutes for herring and sardines.
f. The pressure-cooked fish are dried in a cool, shady and breezy place for 20 to 30 minutes or until a thin slimy skin or pellicle is formed on the surface.
g. The fish are hot-smoked at temperature ranging from 66OC to 88OC for 1 to 3 hours depending upon the size of the fish.
h. The smoked products are weighed and packed in waxed paper ready for the market.
Procedure in Cold Smoking Fish
a. Weigh the fish and wash with freshwater.
b. Remove the viscera by ripping out the gills through the operculum. Be sure the isthmus is not destroyed.
c. Rewash the fish with freshwater.
d. Soak the fish in saturated brine solution for two hours.
e. Pressure-cook or brine-cook the fish following the
f. The pre-cooked fish are laid on bamboo racks and dried in a shady place for 1 to 3 hours or until the pellicle forms on the surface.
g. Cold-smoke the fish at temperatures ranging from 32OC to 43OC for 7 to 14 days. Thin smoke is applied during the first two days and thick smoke for the remaining days.
h. Weigh and pack the smoked products in waxed paper ready for the market.
Methods of Storing Fish While Curing
When curing fish with salt prior to drying or salting it is important that the fish being cured must be properly stored in order to prevent deterioration of the fish as a result of contamination due to careless handling during storage and improper storage practices. While curing, the fish must be protected from possible contamination so the salting trough, curing tank or wooden vessel with fish and curing solution must be covered to prevent contaminated air, flies and other carriers of germs and microbes from coming in contact with the fish. The processor must see to it that the fish being cured are stored in a cool place.
Below are some methods of storing fish while curing:
1. Dry storage method involves storing the fish being cured in an area with a moderate room temperature of 10˚C (50˚F) to 21˚C (70˚F) and a relative humidity of 50% to 60% to maintain the freshness or good condition of the fish. Sunlight must be prevented from getting into the room because it generates heat resulting to an increase in the temperature which is conducive for microbial growth and activity.
Dry Storage Medium for Cured Smoked Fish
2. Refrigerated storage method is done when storing the fish being cured in storage areas with refrigerators. This method slows down microbial growth and preserves the good quality of the fish while curing it. With a refrigerator, a temperature of 3˚C (38˚F) is maintained. The processor must make sure that the fish being cured are kept at an ambient temperature if this method is done.
A Refrigerator for the Refrigerated Storage of Fish while Curing Temperatures Ideal for Storing Fish While Curing
Temperature is a vital factor to consider when storing fish while curing because it greatly affects the maintenance of the good quality of the fish. Spoilage organisms like the bacteria become more active at higher temperatures hence the need to keep the fish in a low temperature. Low temperatures slow down microbial activity thus delaying or preventing the onset of spoilage. Fishes being cured with salt can be kept at a normal room temperature of about 35˚C. Below are other ideal temperatures for keeping fish while curing:
1. moderate room temperature of 10˚C (50˚F) to 21˚C (70˚F) 2. a refrigerated temperature of 3˚C (38˚F)
A Fish Cooling Device
It must be noted that all bacteria do not have the same temperature requirements for growth. A knowledge on this will help a processor determine the ideal temperature most appropriate for storing a particular kind of cured fishery product.
Below are the classification of bacteria and their temperature growth range:
1. Psychrophilic bacteria grow within a temperature range of 0˚C (32˚F) to 21˚C (70˚F). These the troublesome microorganisms because they are capable of multiplying at both refrigerated and room temperatures. Most are spoilage organisms.
2. Mesophilic (middle range) bacteria grow at temperatures between 21˚C (70˚F) to 43C (110F), with most rapid growth at a temperature of 37˚C (98.6˚F). preserves the fish by lowering the moisture content through the process of osmosis, whereby the moisture in the body of fish is removed while salt enters it through the skin as semi - permeable membrane. The flow of water is from a lesser to greater concentration. Thus, when fish is soaked in a concentrated brine solution, the water inside flows out rapidly through the skin. Eventually, when the concentration of the solution inside the cell walls into the protoplasm equals that of the brine, the salting process is completed and the fish is said to be thoroughly struck.
Submerging the fish in the curing solution will facilitate a thorough exposure of the fish muscles to the curing solution thereby hastening the removal of moisture from the fish and the penetration of salt into the cells of the fish. If the fish are kept submerged all through out the curing period, the fish will be completely salted. To make sure that the fish are completely submerged in the curing solution, they must be covered with a woven bamboo cover known as panakip.
LET US REMEMBER through drying or smoking, they are first cured with a brine solution to lower the moisture content, improve the texture, and impart a desirable salty taste.
HOW MUCH HAVE YOU LEARNED?
Post Test
Multiple Choice: Directions: Choose the correct answer from the options given. Write only the letter of your choice in your test booklet. c. To lengthen the storage life of the fish d. To improve the texture of the fish
2. What method of curing fish with salt starts with rubbing the fish with dry salt granules before packing them to allow the formation of brine?
a. to reduce moisture content through osmosis b. to improve texture and taste of fish
c. to destroy microorganisms through plasmolysis of microbial cells
d. all of these
4. One of the steps involved in smoking fish is drying the pre-cooked fish for 1 – 3 hours. Why is it done?
a. to slightly dry the fish b. to slightly harden the fish c. to facilitate formation of pellicle d. to kill the microorganisms
5. Why are drying and dehydration considered as a curing method of preserving fish?
a. because the fish is first treated with salt before drying naturally or artificially
b. drying and dehydration involves the removal of moisture from the fish
c. because the fish muscles harden and cannot be acted upon by enzymes and microorganisms
d. none of these
6. While curing the fish with brine, why do you need to cover the curing container?
a. to shorten curing time
b. to prevent contamination with germs and microorganisms from the air and flies
c. to hasten the curing process d. to prevent adulteration
7. Why is it important to keep the fish being cured at room temperature or at a low temperature?
a. to slow down microbial activity
b. to maintain the good condition of the fish being cured c. both a and b
d. to harden the fish while curing
8. Fish being cured with the curing solution like brine must be thoroughly submerged into the brine __________.
a. to keep the flies from coming in contact with the fish
b. in order for the fish to be thoroughly cured with the curing solution
c. to prevent contamination of fish while curing d. to thoroughly preserve the fish
9. What happens if the fish being cured are kept in a place with a poor ventilation or quite hot?
a. the fish will not be thoroughly cured
b. the quality of fish will deteriorate due to microbial action c. microbial activity increases resulting to spoilage
d. both a and b
10. To keep the fish submerged in the curing solution, which of the following will you do?
a. cover with a ‗panakip‘
b. cover with banana leaves c. cover with a metal basin d. cover with old newspapers
Practical Demonstration with Oral Interview:
Demonstrate these tasks:
1. Hot smoking of fish
2. Dry storage method of storing fish while curing
LET US APPLY WHAT YOU HAVE LEARNED