Post Harvest Technology in Fish

The need for proper handling and processing of fish is important both for the fishing industry and for the consumers.

• Improvement of the processing and handling of fish in terms of quality, product range and volume results in increased economic activity and employment.
• It is also one way of stabilizing fish marketing by providing an outlet for surplus and peak catch even during emergency harvest, thereby ensuring high fishing activities and stable prices.
• It can also contribute to the efforts related to nutritional goals.

Handling

• The quality of fish depends on how it is handled from the time it is taken out from the water until it reaches the kitchen.
• Fish landed is usually subjected to rough handling treatments.

Consider These 3 Cardinal Rules in Handling Fresh Fish

1. Cleanliness:

• Observe cleanliness throughout the fish handling chain.

2. Care:

• Work on fish as quickly as and as promptly as possible.
• Sort fish properly before packing.
• When fish have to wait on deck or on the fish landing for some time before working on these, cover these to protect them from heat and other elements.
• Drain fish before icing
• Avoid brushing the fish
• Don’t throw, trample or kick the fish

3. Cooling:

 Temperature is the most important single factor affecting the quality of fish.

• Use plenty of ice. Put additional layer of ice on top, bottom and side of fish in boxes or shelves
• Don’t over-fill a box or shelf. The next box or shelf on top will smash the fish below.
• Lay the fish belly downward – this prevents entry of dirt water into the fish.
• Don’t pack fish so tightly that melted ice cannot flow.
• Fish is cooled more quickly when ice cold water is poured on them. Fish spoils easily when allowed to stay in stagnant water, blood or slime.
• Store fish in ice as quickly as possible. Make sure the fish room is always kept clean.

Transportation:

• Fresh fish transported to far distances must be packed with ice to ensure freshness when they reach the consumers.  
• Proper packing of fresh fish with ice means arranging the fish and ice alternately in the container to maintain chilling temperature.
• It is attained with the ratio of 1 kg of ice to 2 kg of fish.
• The more sophisticated method of the transportation is the refrigerated truck or Insulated Van.
• When transporting fish within the region, wholesalers pack them in ice. Upon reaching their destination, fish are repacked with ice and sold to retailers and eventually to consumers.
• The latest practice of transporting live marketable fish.

Processing:

• Fish spoils very quickly within 12 hours after being harvested.
• This due to the high ambient temperature that is ideal for bacterial growth.
• To prevent contamination of the fish, proper hygiene must be ensured.
• Contamination can come from people, soil, dust, sewage, surface water, manure, or spoiled foods.
• Poorly cleaned equipment, domestic animals, pets, vermin or  unhygienically slaughtered animals can also be the cause.
• To prevent spoilage of the harvested fish, either the bacteria present in them must be killed or their growth must be suppressed.

Different methods exist to suppress bacterial growth:

Salting:

• This is an inexpensive method when salt is cheap, as no electricity is necessary and storage can be at room temperature.
• Fish quality and nutritional value are reasonable after salting.
• Storage life is long.

Drying:

• Inexpensive method as no electricity is required and little equipment is needed.
• Dry and / or airtight storage is required.
• Quality and nutritional value are reasonable if storage is good.

Smoking

• Inexpensive, little equipment and energy needed, but fuel must be available.
• Quality and nutritional value are reasonable.

Fermentation:

• This method is often inexpensive, but the fish taste and odour are radically changed.
• Storage life varies depending on the product.
• Nutritional value is often high.

Canning:

• This is a fairly expensive method. Because, it is labour intensive and requires plenty of energy, water and equipment, such as tins or jars with lids, sterilisers and canning machines.
• Packaging is expensive. Storage is easy and possible for long periods (below 25 °C / 77 °F).
• Quality and nutritional value are good.

Cooling and Freezing:

• This is a very expensive method. Because, it involves high use of energy and large investments in equipment.
• Quality and nutritional value of the product are good and storage life is long.

Sun drying is the most common processing method practiced in India. It is also the simplest and least expensive way to preserve fish. The steps in drying fresh fish are

1. Split the fish into butterfly fillets along the backbone with a sharp knife.
2. Remove the gills and internal organs or the entrails.
3. Wash fish to remove all traces of blood.
4. Immerse split fish into a brine solution of 1 part salt to 3 parts water for 30 minutes to 1 hour depending on the size of fish.
5. Drain the fish and dry under the sun for 1 to 2 days.
6. Store dried fish in a cool, dry place.

Smoking of Fish

1. Remove the gills and entrails
2. Wash and soak in brine solution (1:3 salts to water) for 30 minutes to one hour depending on the size of fish.
3. Boil in 10% brine solution (1 part salt to 9 parts water) for 10 to 20 minutes.
4. Smoke for 30 minutes at 43-66°C.
5. Pack in plastic bags and refrigerate.