Spoilage is significantly affecting the shelf life of fish.

Fish are known to be an excellent source of protein, crucial for muscle development.
Term for the condition when gas accumulates in the gut, leading to spoilage. BELLY BURST

Fish are freshwater animals that are used as food. They are a good source of protein, minerals,
vitamins, and iodine. Fish meat is easily digested and absorbed by the body.
Fish make a nutritive and palatable dish both in their fresh and preserved forms.
There are reasons when fish are abundant. During this season, the fisherman and the fish
vendors faced with several problems. One of them is inadequate storage facilities. Another is
transportation. The only solution to prevent many of our fishery products from being spoiled is
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 product.
The principles behind fish preservation are to (1) prevent or delay microbial
decomposition of fish; (2) prevent or delay self-decomposition of fish; and (3) prevent other
causes of spoilage of fish like physical damages.

Preparation for Fish

Fish is easily spoils. Their freshness last for a very short period of time. Hence, they
should be cleaned and cooked immediately to retain their good taste and high nutritive value. If
cooking is not possible, store them in a cold storage to prolong their good condition. Shellfish
should be held in tight containers frozen at low temperature.
Fish is always tender and requires short cooking time. It requires careful handling to
avoid breaking of coagulate protein and soften connective tissue, thus making it more digestible.
There are many possible methods of fish preparation. You may add sauce, vegetables, and other
ingredients to enhance the taste and increase nutritive value.
Fish maybe broiled, baked, fried, boiled, and steamed. Oyster may be served raw with
condiments, with sauce or cooked. They may be boiled in shells, panned or baked. Clams are
most frequently served steamed in shell. Lobsters are best when boiled with salt. Crabs should be
washed carefully. Dry them well and cooked or pan fry. Fresh shrimps are boiled; shells
removed and cut the back. Uncooked shrimps are best added to baked products.

Sizes and Market forms of Dressed Fish

1. Whole or round fish are sold in this form where all parts of the fish are still intact.
2. Drawn fish – this form is sold with the internal organs are removed.
3. Steaks – bigger fish like Tanique, tuna, maya-maya, lapu-lapu, and others are sold chopped or
cut along the cross section.
4. Dressed fish – the scales, internal organs, fins, head, and tail are removed.
5. Fillet – the most common cut and available from any fish – round or flat. Fillets from larger
fish can be further cut into portions sized supreme or scallops.
Types of Fish Fillets
a) Butterfly fillet – smaller whole fish, (typically 300-400g), can be prepared by removing the
head and cutting through either the back or belly side of the fish. The two
small fillets remain joined along one side, creating a butterfly fillet when
opened.
b) Quarter-cut fillets – this is a single flat fish fillet that can be cut in half lengthways into quarter
fillets.

c) Sticks – this is cut form fillets or steaks. They are usually form fish that has been minced and
shaped, breaded, and frozen.

d).Live fish – dalag (mudfish), hito (catfish), and tilapia are usually sold alive.

Enzymes – these are protein present in the muscles, organs, and gut of the fish (and all
animals)
 Metabolic enzymes are the “workers” In the body and helps to spend up processes such
as digestion.
 Digestive enzymes break down food until the gut can absorb the nutrients in the food.

Term for the condition when gas accumulates in the gut, leading to spoilage. BELLY BURST

The principles behind fish preservation are to

(1) prevent or delay microbial decomposition of fish;
(2) prevent or delay self-decomposition of fish; and
(3) prevent other causes of spoilage of fish like physical damages.

Butterfly fillet – smaller whole fish, (typically 300-400g), can be prepared by removing the
head and cutting through either the back or belly side of the fish. The two
small fillets remain joined along one side, creating a butterfly fillet when
opened.

Dressing a Fish
1. Remove the scales of the fish.
2. Cut the tail and the head.
3. Remove the fins by making a cut along both sides.
4. Remove the entrails.
5. Using a knife, scrape all blood, and false kidney.
6. Wash the fish thoroughly.
Boning a Herring
1. Cut off the head, tail, and fins and slit the fish open along the belly.
2. Flatten out the fish and firmly press along the length of the backbone.
3. Start at the head end and with the knife point, ease out the backbone.

Steps in preparing a fish.

-Beheading
-Gutting
-Bleeding
-Cutting
Bacteria – it is responsible in the breakdown of plant and animal material and the possible return
of simple inorganic compounds to the soil. The result of this breakdown is
spoilage, fermentation, and decay. Since fiat is an organic matter, it spoils easily.
As soon as it dies, bacteria act on it.
Bacteria are simple and very tiny organisms. They live almost everywhere including –
a) air – streptococcus
b) land – bacillus
c) sea/ocean floor – archaebacteria
d) plants and animals – cyanobacteria, bacillus
e) skin, gills, and guts of fish – proteobacteria, cyanobacteria, and firmicutes
Bacteria are classified according to shape and to their temperature requirement. Bacteria
classified to shape are the following:
a) coccus – round

b) bacillus – rod-shaped
c) spirillus – spiral

d) staphylococcus – grapelike
e) streptococcus – chainlike

Bacteria classified according to their temperature requirement are as follows:

a) thermophilic – thrives at high temperature (heat loving)
b) psychrophilic – thrives best and low temperature (cold loving organisms)
c) mesophilic – thrives between low and high temperatures
2. Enzymes – these are protein present in the muscles, organs, and gut of the fish (and all
animals)
 Metabolic enzymes are the “workers” In the body and helps to spend up processes such
as digestion.
 Digestive enzymes break down food until the gut can absorb the nutrients in the food.

The body can then use the nutrients for growth and energy. When a fish dish, enzymes
keep working in the body, causing changes in the flesh. The digestive enzymes continue to break
down the food in the fish’s gut. If the fish is ungutted, the enzymes begin to eat holes through the
gut lining, allowing bacteria to enter the flesh and break it down. Sometimes the gut cavity
swells up with gas and eventually bursts, making it even easier for bacteria to enter the flesh.
This is known as “belly burst”
Changes in Fish after Death

1. Changes in appearance – the color starts to fade until it becomes dull as spoilage progresses.
2. Rigor mortis – characterized by the stiffening of the muscle tissue. This state lasts only for a
few minutes in some fish, to several hours in others. The fish in this state is
considered fresh.

3. Autolysis – the breakdown of tissue caused by enzymes. Since it softens the tissue, it proves
the activity of microorganism.
4. putrefaction – the state when the components of the flesh are in assimilable forms. It is
accompanied by a foul odor, which is the result of the breakdown of protein.
The fish at this stage is spoiled and undesirable.
Proper Steps in Handling Fresh Fish
1. Avoid exposing the fish to the 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.
Characteristics of Fish and Stale Fish
Fresh fish Stale fish
Eyes Bright and full, not sunken Eyes sunken or completely
shrunken, covered with slight
to thick slime often yellowish
in color
Gills Bright colored, clean, free Dull brown or gray, slime
from slime, and offensive cloudy, sour and offensive
odor odor under gills cover
Flesh Firm and elastic to the touch, Soft and limp, flappy and pits
white or bluish-white and on pressure, reddening along
translucent, no discoloration, the backbone, easily tears
adheres firmly to the bone from bone, blood under tissue
and difficult to tear, blood sound brown or chocolate
under tissue sound red in colored
color
Belly walls Intact Often ruptured, viscera.
Protruding
Muscle tissue White Pinkish, especially around
backbone
Vent Pink, not protruding Pale brown, protruding
Odor Fresh, fishy odor Stale, sour, or putrid
color Bright Faded and dull