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View the documentSalted-fish drying
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Salted-fish drying

Fisheries cover the whole operation of catching fish, processing or preservation and marketing of the product.

Due to the acute shortage of ice and lack of storage facilities in their villages, most fishermen have resorted to fish processing as an alternative for saving their catch from rapid spoilage. Fish can only last 12-15 hours in fresh condition after catching.

Preservation of fish is often an opportunity to use underutilized family labor and generation of employment in coastal areas. Salted dried fish processing is mostly done by women, children and unemployed youth who cannot go fishing.

Fish is easily spoiled due to microorganism activity (bacteria, etc.), chemical deterioration (breakdown of fats or enzymatic activity) and infestation (blowfly insect or vermins). There is no simple solution to spoilage, but there are preservation methods which can be applied to inhibit perishability. Deterioration starts when the fish die; and to slow down perishability, salting and drying fish is one process. In many cases, preservation improves product/market preference, increase quality and storage life and commands better prices.

Principles of salting and drying

Salt solution removes water from the fish flesh to a point where microbial and enzymatic activities are inhibited. Salty concentration of 6-10 percent in the fish tissue will prevent bacterial activity (UNIFEM, Food Technology Source Book, No. 4 1988). Microorganisms. known as hallophilic bacteria, are, however, saltloving; but, drying will stop these bacteria. Salt will penetrate into the fish flesh until the concentration is equal to the outside where no movement of water or salt occurs. The brine solution can be used further by boiling to remove surface foam and adding more salt as required. Boiling of the unused brine solution by evaporation will result to crystal salt recovery; but processors do not practice this.


Soaking vats or tubs made of wood

Drying is the transfer of moisture from the product to the air. The two stages of drying is the removal of (a) surface moisture and (b) the internal moisture from the fish. Drying is effected by (a) air movement and (b) heating by the sun. Sun-drying salted fish is the common practice in the Philippines.

Methods of salted fish drying

The use of crystal white coarse salt is preferred. Preparation of the brine solution is generally practiced in the Philippines, using three mixture ratios to suit various fish species and consumers' preference. They are:

1. 50 kg (1 sack) salt is dissolved in 100 liters water (strong solution)—Ratio 1:2
2. 50 kg salt is dissolved in 150 liters water to form a medium brine solution—Ratio 1:3.
3. 50 kg salt is dissolved in 200 liters water to form a light brine solution—Ratio 1:4.

Mix the solution thoroughly by continuously stirring with a wooden paddle until all the salt is dissolved. Use wooden tubs or vats as brine containers. This can be a discarded wooden boat or dugout or fabricated lumber.

Clean the fish thoroughly from slime and dirt by washing them in clean water. Drain the fish in about 20 minutes and soak them in the brine solution for two to five hours. Soaking time depends on the species of fish. Small fish, like sardines and mackerels, normally requires two to three hours. Large fish are soaked for three to five hours. Usually, large species need splitting and removal of gills and guts. The size, oil content and flesh texture determine immersion time. Quality of salted dried fish depends on the state of freshness prior to processing.


Mixing ratio of brine solution: 1 sack salt/50 kg mixed with 5 kerosene cans (20 liters) water.

After soaking, dry them in mats (bamboo or burl), nets, trays, bamboo slats or covered ground. Drying can last from three to six days depending on light intensity, wind movement, fish species and thickness of flesh. An indication of well-dried fish is the reduction of weight from, 65-75 percent or moisture content of dried fish from 14-18 percent.

Many commercial fish-drying areas are located in isolated small islands or far from population centers which are free from house fly (bangaw or langaw). The blowfly usually lay their eggs during drying and, later, the eggs hatch into maggots or worms that damage the processed fish. Thorough drying will minimize rotting. Do not use insecticides as commonly practiced in many places, because of their harmful effects to health.

The dried fish are usually packed in wooden crates with wax paper lining or corrugated boxes with newspaper lining for shipments. For local marketing, wooden, bamboo or rattan baskets are used.


Tray method of drying salted fish.

Economics of production—salted-dried fish (Roundscad)


Value (in pesos)

Total value (in pesos)




Annual Return


1,300 kg dried fish/month at P27.50/kg × 10 months


357,500

Annual Production Cost


30,000 kg fish × P10/kg

300,000



7,200 kg salt × P1.30/kg

9,360



13,000 pcs plastic bag × P0.08/pc

1,040



Water at 4/day × 200 days

800



(2) laborers at 25/day × 200 days

10,000



Interest

3,726



Depreciation

171325,097


Fixed Investment


(1) unit brining tank

200



(1) unit plastic sealer

290



Knives and other utensils

20



(20) pc drying trays at P3/pc

60

570

Net return


Annual return

357,500



Less: Annual production cost

325,097

32,403

Return on Investment



Net return

32,403


Fixed investment

570

56.85

Source: Technology of Improved Drying Method of Roundscad, PCAARD, Vol. Vl, no

3/84,1994