123foodscience.com

 

 

 

Home

Home

Food Nutrition

Food Chemistry

Food Microbiology

Food Packaging

Food Preservation

Food Processing

Food Additives

Food Analysis
Food Safety

Food Spoilage

Food Dictionary

News   New

Submit Article

view Article

Free Members Join

View members

Submit industry

View industries

Post Jobs

Job Vacancies

Post Institute

List Of Institute

Site Map

Contact Us

 

FISH PRESERVATION TECHNIQUES

Drying
Smoking
Freezing
Vacuum packing
Salt
Sugar 
Pickling
Canning and Bottling
Jellying
Irradiation
Modified atmosphere

Controlled use of microorganism
High pressure food preservation
Fish preservation techniques
MIcrobial Safety in Food Preservation
 

Different types of preservation methods such as drying, smoking, freezing, chilling, brining, fermentation and canning are reported to extend the self-life of sea foods and meat products. However, low temperature storage and chemical techniques for controlling water activity, enzymatic, oxidative and microbial spoilage are the most common in the industry

Low temperature storage

This method preservation does not kill the microorganisms but reduces microbial metabolism which is responsible for spoilage. The use of ice or other methods of chilling is recommended to keep the fish all times in a cool condition before freezing. The functions of ice include: (a) maintaining uniform low temperature, (b) reducing autolysis and bacterial degradation and (c) providing a gentle  washing/cleaning effect.                                                      

Controlling water activity

Although freezing is the best way to inhibit microbial growth (except psychrohpiles and spores) and slow chemical changes thereby preserving fish for a longtime, it is an energy intensive operation and can only be used as a temporary method of preservation. Most of the psychrohpiles and spores survive during freezing and grow during thawing. Fish spoilage can be prevented by controlling water activity. Therefore, lowering water activity (aw) can minimize putrefaction and improve preservation of fish. The term water activity (aw) refers to the water which is not bound to food molecules and can support the growth of bacteria, yeasts and moulds (fungi). The control of water activity in fish is accomplished by drying, adding chemicals, or a combination of both methods. Sugars and sodium chloride have been used to bind up the free water molecules and create an osmotic imbalance resulting in cell growth inhibition.

Controlling autolytic enzymatic spoilage:

This can be accomplished by removing the enzymes or by developing techniques that inhibit their activities. Gutting of the fish immediately after capture can avoid the invasion of digestive tract proteases through the abdominal cavity to the tissue and prevent or slow degradation.

Sodium chloride has shown the ability to inactivate autolytic enzymes in marine species. The fish were stored in sea water at 1C with the addition of lactic/acetic acid or propionic acid to lower the pH to 5. After a storage period of 35 h, they found that lactic acid was effective in reducing the percentage of belly bursting.

Controlling oxidative spoilage:

In order to inhibit lipid oxidation, the free radical mechanism catalysts (molecular oxygen and transition metals) need to be removed. By removing these catalysts through antioxidants and chelating agents, lipid oxidation can be limited and the lipid yield improved. An index often used to determine lipid oxidation is the measurement of Thiobarbituric Acid Reactive Substances (TBARS). Among lipid oxidation inhibitory additives are: Phenolic antioxidants (Derivatives of phenol such as Butylated Hydroxyanisole (BHA), Butylated Hydroxytoluene (BHT) and Tertiary Butylhydroquinone (TBHQ)) and ethylenediaminetetraacetic acid (EDTA is a member of the polyaminocarboxylic acids group which can be added to fish to remove trace metals through chelation that may act as prooxidants).