Studies of Fish Spoilage: VI. The Breakdown of Carbohydrates, Proteins and Amino Acids During Spoilage of Cod Muscle Press Juice

Abstract

Autolytic changes in cod muscle press juice are negligible in proportion to the changes resulting from bacteria ordinarily contaminating the press juice during its preparation. During early spoilage, the greater part of the bacterial action on expressate even in intimate contact with air is the result of anaerobic growth. Later, when the press juice is definitely spoiled, aerobic oxidation assumes the major part if air is available. Spoilage in sea fish expressate always occurs in two stages irrespective of the availability of air, first the oxidation of lactic acid and sugar, and second that of amino acids and the hydrolysis of proteins. The second stage represents advanced spoilage. As trimethylamine production occurs mainly during the first stage, it is a good criterion as to the probable production of toxic compounds resulting from protein and amino acid breakdown.