Q. Explain the factors on which Spoilage of fish depends?

i) The type offish. Different types of fish are susceptible to spoilage due to shape and size. A fat fish is susceptible to spoilage due to the oxidation of unsaturated fats of their oils, whereas, the thin variety may get spoilt due to the rapid setting of rigor mortis (stiffening).

ii) The initial microj7ora: The flesh and internal organs of fish are normally sterile at the time of catching but the external skin, gills and the intestine may contain bacteria depending on the environment it has been caught. If they are caught in polluted waters, the microbial load will be higher.

iii) The temperature of air and water source: The type of microorganism on the fish depends greatly on the location. The fish from warm seas are contaminated with the mesophilic strains while the fish caught in cold regions contain

iv) Handling of the fish after being caught: The handling process after catching the fish is also important to its spoilage. The fish after catching are held either as whole, beheaded or gutted (the intestines are removed). The spoilage pattern differs for each, the gutted fish keeping longer. The immediate storage pattern also plays a role. Sometimes, the fishes are piled, creating pressure on the lower layers of fish. If ice is used in preserving the fish, it also contributes to the microbial load, as ice is generally manufactured with unpotable water. The cross contamination from earlier catches, the nets used, boats, baskets or other containers used and their sanitary conditions also play a role.