BACTERIAL MICROFLORA IN MARINE FISH AND E VALUATION OF SPOILAGE

The nature of the bacterial microflora of fish is directly linked to t he environment. In cold and temperate waters the initial microflora of marine fish is dominated by psychotrophes and Gram negative bacteria. While in warm waters Gram positive mesophiles predominate. The princi pal bacteria responsible for spoilage are strict aerobes and notably b acteria of the genus Pseudomonas are implicated. Independently of the temperature of the waters of origin and therefore of the composition o f the endogenous microflora, conservation in ice selects the same spoi lage bacteria. Tissular enzymes have a determinant role in the first s tages of spoilage. Later on the bacteria which infest muscular tissue become the principal factors responsible for degradation. The evaluati on of spoilage by counting bacterial microflora is not very reliable, however the measurement of amines permits in many cases the determinat ion of the level of degradation. A approach is suggested in order to u se the measurement of volatile amines. Work is undeway to explore the possible use of biogenic amines, which result essentially from the act ivity of microbial decarboxylases. Nevertheless, the evolution of amin es is not significant in the very early stages of spoilage. Therefore, at the present time research is oriented towards the phenomena of aut olysis, namely ATP breakdown.