Bacterial Decomposition of Extractive Matter of Meat of Aquatic Animals

Abstract

So far as I am aware, little is known of the relation of the age of an animal to the rate and the velocity of the bacterial decomposition of it. According to HUNTER, (1) in salmon, which are actively feeding when caught, enzymic decomposition as well as bacterial decomposition may take place. It has been found that immature salmon caught on the feeding ground, with alimentary tract full of feed, is decomposed in a manner different from the mature salmon caught on the spawning migration after the fish have ceased feeding, and when the alimentary tract is empty. In the immature feeding salmon enzymic decomposition accompanies bacterial spoilage, causing a softening of the belly wall and disintegration of the viscera of the fish. In mature salmon caught on the spawning migration, the alimentary tract is sterile since no food is present and invasion by bacteria in such fish is solely from the outside inward. After the salmon have reached the spawning grounds, the type of spoilage again differs from that of the mature migratory salmon even though the bacterial flora in both are almost identical.(2) The chemical composition of the meat may vary with time in the life-cycle of the animal. Therefore, it seems that the rate and the velocity of the bacterial decomposition depend also upon the time in the life-cycle of the animal at which it is caught. The present paper embodies my observations on the rates and the velocities of the bacterial decomposition of extractive matter of meat of aquatic animals of different ages, and on the growth rate of bacteria in the solution of the extractive matter.