Fish Preservation

Fish preservation is the method of extending the shelf life of fish and other fishery products by applying the principles of chemistry, engineering and other branches of science in order to improve the quality of the products.

Preservation methods maintain the quality of fish for a longer period of time.

Proper steps in handling fresh fish

1. Avoid exposing the fish to sunlight. Keep them in a shaded area.

2. Ice the fish immediately after they are caught to lower their temperature.

3. Remove the gills and internal organs.

4. Avoid soaking the fish too long in the water after death as this easily spoils the fish.

5. Use mechanical refrigeration if there are facilities.

Methods of fish processing

a. Curing

b. Icing

c. Freezing

d. Canning

e. With the use of additives or chemicals

Fish curing is defined as the method of preserving fish by means of salting, drying, smoking and pickling.

a. Salting — Salt is the preservative agent used to lengthen the shelf life of fish and fishery products. This is used in almost all methods of preservation except in icing, refrigeration and freezing.

Methods of salting fish

1. Kench - salting or dry salting. The fish is heavily salted with the ratio of 1:7 (1 part fish to 7 parts of salt). Before, they are heavily salted, the fish are soaked in 10% brine to leach out blood and then half dried for two hours. They are packed in wooden boxes to drain away. Ex. Some fish commonly kenched are Indian sardines, short-bodied mackerel, stripped mackereland yellow-striped crevalle.

Procedure:

1. Weigh the fish.

2. Clean the fish and wash them with fresh water. The scale may or may not be removed.

3. Soak the fish in 10% brine, 1 part salt to 9 parts water, for 30 minutes to leach out blood.

4. Half dry the fish for two hours

5. Salt them with the proportion of 1:7 (1 part fish to 7 parts salt).

6. Pack the fish in wooden boxes.

Steps in dry salting to make brine:

1. Weigh the fish.

2. Clean the fish and if their flesh is thick, make a long deep cut on them.

3. Wash them with fresh water and soak in 10% brine for 30 minutes to leach out the blood.

4. Drain the fish for one hour.

5. Rub thoroughly each fish with salt so that all surfaces are coated.

6. Pack the fish in layers of salt in concrete jar or tank with salt sprinkled be­tween layers so that the brine formed covers the fish. The proportion of salt to fish is 20% (1 part salt to 4 parts fish), or 25% (1 part salt to 3 parts fish) by weight.

2. Brine salting — . Fish that are commonly brine salted are anchovy and herring.

Procedure:

1. Weigh the fish and wash them with fresh water.

2. Mix salt with the fish in a proportion of 20% or 25% by weight.

3. Let the mixture stand for 24 hours.

4. Decant the brine formed.

5. Boil the brine formed together with saturated brine for 30 minutes and let it cool.

6. Pack the salted fish in a glass jar.

7. Pour the boiled brine into the salted fish.

8. Place rack and weight on top of the fish to keep them below the surface.

9. Cover the container.

3. Fermenting — is the making of fish paste and fish sauce.

Procedure:

1. Weigh the fish.

2. Cut into small pieces if fish are large.

3. Wash and drain for 30 minutes.

4. Thoroughly mix salt with the fish in a proportion of 1:4 (1 part salt to 4 parts, fish) by weight.

5. Add papain to shorten the fermentation period.

6. Pack the fish in a concrete tank or jar.

7. Store for about a month to a year so that the aroma will develop caused by the breakdown of fish proteins.

8. Separate the fish sauce from the paste.

9. Extract the fish sauce and pack in bottles.

Drying and Dehydration - Drying is the process in which moisture is removed by exposure to natural air current as humidity is regulated by climatic condition. Dehy­dration is the process of removing moisture with the use of mechanical device that provides artificial heat for drying.

Methods of fish drying

1. Salt Drying - the method of drying fish where the fish are sprinkled and blended thoroughly with dry salt before drying under the heat of the sun.

2. Brine Salting - the fish are soaked in a saturated brine solution for a few hours prior to drying under the heat of the sun.

Drying Procedure

1. Whole or round

a. Small fresh fish like herring, sardines and others are weighed then washed thoroughly with marine water.

b. Remove the viscera by ripping out the gills through the operculum, making sure the isthmus is not destroyed.

c. Wash again with marine water.

d. Dry salt or brine the fish. In dry salting the fish are sprinkled and blended thoroughly with dry salt with the ratio of 1:3 or 1:4. Let the mixture stand for 5 to 7 hours for it to undergo osmosis.

e. Rinse the salted fish in water.

f. Place the fish in a woven bamboo rack and are dried under the sun for one and a half day.

g. When dried, weigh the dried fish and place in clean wooden boxes ready for market.

2. Spit dried fish

a. Medium-sized fresh fish such as short bodied mackerel, striped mackerel and others are weighed and washed with marine water.

b. Split the fish and remove the viscera.

c. Wash them again with marine water.

d. Salt the fish, dry or brine, with the same proportion and let it stand for 5 to 7 hours.

e. Rinse with fresh water.

f. Place in a woven bamboo rack and dry under the heat of the sun.

g. When dried, weigh and place in clean wooden boxes ready for market.

Dehydration Procedure

1. Fresh fish like yellow fin tuna and sharp-nosed shark are weighed and washed with freshwater.

2. Cut into fillets.

3. Washed again and soak in 20% brine solution for 5-7 hours.

4. Precook for 30 minutes.

5. Lay on aluminum trays and place inside an oven for artificial drying.

6. From the oven, dehydrated fish meat are packed in plastic bags ready for market.

. Smoking — This is the method of preserving fish by applying smoke with the aid of
salting, drying and heat treatment. Smoked fish.

Types of smoking

a. Hot smoking - This is a slow type of broiling where fish are placed near the fire at
smoke temperature.

b. Cold smoking - The fish are placed away from the fire at a distance of almost two
meters with a smoke temperature ranging from 32°C to 43°C.

Procedure in cold smoking

1. Weigh and wash the fish with fresh water.

2. Remove the viscera by ripping out the gills. See to it that the isthmus is not destroyed.

3. Rewash the fish with freshwater.

4. Soak the fish in saturated brine solution for 2 hours.

5. Pressure cook or brine cook or boil in a 10% brine solution for 10 minutes.

6. Lay the precooked fish on bamboo racks and dry in a shady place for 1-3 hrs. or until the pellicle forms on the surface.

7. The fish are cooled smoke at a temperature of 32-43°C for 7 to 14 days. Apply thin smoke during the first two days, and thick smoke for the remaining days.

8. The smoked products are weighed and packed in wax paper ready for market.

Smoke-producing materials: sawdust, corn cobs, rice hull, guava leaves, coconut husk, dried sugar cane stakes, pili nuts shell, and tea leaves

d. Pickling — This method of preserving fish is usually done in making appetizer which
is considered semi-preservation because its shelf life is short. This method is used for
home consumption only.