Smoked mackerel fish (Scomber scombrus) is associated with microorganisms which are capable of causing spoilage. A 1g of the fish sample was made and serial dilution of 1: 10^-1 to 1: 10^-5 were made from 10ml of the fish sample. From the dilution, 1ml of each diluent was plated on nutrient agar to permit the growth of the common bacterial organisms from the spoiled smoked mackerel fish (Scomber scombrus). Duplicate plate were performed to each dilution. The plate was stirred gently to ensure even distribution of diluent and was incubated in inverted position at 37⁰C for 24 hours. After 24 hours the colonies were counted. Gram staining was carried out on the colonies and examined microscopically alongside other biochemical tests to identify the microbial load of Bacillus spp, Lactobacillus spp, Salmonella spp and Micrococcus spp. This indicates that smoked mackerel fish is easily spoilt when left for a long time. From the work carried out on the spoiled smoked mackerel fish care should be taken before the consumption in other to save lives.

CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Fish is one of the major sources of animal protein. Protein are very essential in man’s diet as they are one of the important nutrient needed by the body for various metabolic processes and because of their rich nutrient constituents, fish can form a suitable environment for the growth of microorganisms. Fish can be processed for commercial purposes and preserved so that they can remain unspoilt for a relatively long time. There are various ways of processing fish, one of the local method which is widely used in our society include smoking (Heldman, 2005).

Microbes involved in fish spoilage belong mostly to bacteria and include Bacillus spp. Lactobacillus spp. Micrococcus spp and Salmonella spp. When these microbes contaminates and grow on fish, some of them produce toxins that could cause food poisoning when such fish is consumed (Hobbs, 2005).

Some food-borne diseases caused by bacteria of contemporary importance include micrococcal intoxication, botulism associated with tinned foods, Salmonellosis, Bacillary dysentary, Bacillus infection, cholera, brucellosis, tuberculosis and dihtheria (D’Aoust, 2006).

Growth of some microorganisms on fish may take place between harvesting and processing of the fish. Adequate control of temperature of freezing and smoking will reduce such growth (Frazier and Westhoff, 2004).