Fish is an aquatic vertebrate with fins, gills and skin with glandular secretion that decreases friction. A typical fish is torpedo-shaped and usually limbless, with a head containing a brain or sensory organ and muscular tail. Most fish have scales and are poikilothermic. Fish are extremely perishable food. For example, most fish become inedible within 12 hours at tropical temperatures. Spoilage begins as soon as the fish dies and processing therefore should be promptly done to prevent the growth of microorganisms. Fish is a low acid food and therefore susceptible to growth of food poisoning pathogens making this another reason why they should be processed quickly .
Preservation of fish by smoking is carried out after they are catch from water bodies, thereafter smoked fish may be eaten without further cooking. From the processing units to market centres, smokeddried fish are often contaminated with microorganisms such as bacteria, yeasts and moulds.