ABSTRACT
The fl esh of living fi sh is sterile. However, the skin, mucus, gills and the gastro-intestinal tract contain signifi cant microfl ora. The composition of the bacterial community is determined to a large extent by the bacteria in the aqueous medium surrounding the fi sh when it is still in its larval stage (Hansen and Olafsen, 1999) and thus it varies according to a large number of hydrological parameters. The bacterial contents commonly observed vary from 102 to 105 bacteria/cm² in the skin, 103 to 107 bacteria/cm² in the gills and 103 to 105 bacteria/g in faeces (Abgrall, 1988). At the time of fi sh death, there is fi rst a loss of freshness due to autolytic enzyme activity. Then microorganisms present in the fi sh can contaminate the fl esh by moving through the muscle fi bres or by spreading during the processing stages (gutting, head cutting, fi lleting, etc.) and their activity leads to spoilage, characterised by off-odours, taste and degradation of texture.
