EVALUATION OF BACTERIA OF PUBLIC HEALTH IMPORTANCE IN OKPA

ABSTRACT

The study was aimed at evaluating the bacteria of Public health importance in Okpa. Twenty five samples were collected from five different locations and analysed for total aerobic count. The organisms isolated were Staphylococcus aureus, Escherichia coli, Salmonella and Shigella species using standard bacteriological methods. The mean aerobic bacterial count from the different locations ranged from 2.72 x 104cfu/ml to 1.91 x 105cfu/ml. The predominant bacteria was Staphylococcus aureus showing occurrence in all the samples collected from the different locations  with prevalence ranging from 60-100%, which was closely followed by Escherichia coli with prevalence also ranging from 60-100%, Shigella had an occurrence ranging from 20-80% and Salmonella  ranged from 0-60% in occurrence. These findings suggest that Okpa may constitute a source of food poisoning, consequently public health hazards. The need for improvement and maintenance of good hygienic practices by food handlers and vendors in the market could serve as a means for reduction in the level of contamination by these isolated organisms.

TABLE OF CONTENTS

Title page                                                                                                                              i

Certification                                                                                                                         ii

Dedication                                                                                                                            iii

Acknowledgement                                                                                                                iv

Table of contents                                                                                                                  v

List of tables                                                                                                                         viii                  

Abstract                                                                                                                                ix

CHAPTER ONE

1.0 Introduction                                                                                                                      1

1.1 Aim and Objectives                                                                                                          3

CHAPTER TWO

2.0 Literature Review                                                                                                             5

2.1 Bambara groundnut                                                                                                          5

2.1.1 Nutritional composition of bambara groundnut                                                            6

2.1.2 Anti-Nutritional components of bambara groundnut                                                    8

2.1.3 Processing and Utilization of bambara groundnut                                                        9

2.2 Food borne infection and intoxication                                                                             11

2.3 Food borne diseases                                                                                                          12

2.4 Bacteria of public health importance                                                                               12

2.4.1 Staphylococcus aureus                                                                                                  12

2.4.2 Escherichia coli                                                                                                             13

2.4.3 Salmonella                                                                                                                     13

2.4.4 Shigella                                                                                                                          15

2.5 Prevention and control of food borne diseases                                                                 15

2.6 Food Security                                                                                                                   16

2.7 Consumers of ready to eat foods                                                                                      17

2.8 Microbiological Safety                                                                                                     17

CHAPTER THREE

3.0 Materials and Method                                                                                                       19

3.1 Sample Collection                                                                                                            19

3.2 Sample Preparation                                                                                                          19

3.2.1 Sterilization of Materials                                                                                               19

3.2.2 Media Preparation                                                                                                         19

3.3 Viable count                                                                                                                     20

3.4 Identification of isolates                                                                                                   20

3.5 Gram Staining                                                                                                                  20

3.6 Motility test                                                                                                                      21

3.7 Biochemical test                                                                                                               21

3.7.1 Catalase test                                                                                                                   21

3.7.2 Coagulase test                                                                                                                21

3.7.3 Oxidase test                                                                                                                   22

3.7.4 Indole test                                                                                                                      22

3.7.5 Citrate utilization test                                                                                                    22

CHAPTER FOUR

4.0 Result                                                                                                                                23

CHAPTER FIVE

5.0 Discussion and Conclusion                                                                                              27

5.1 Discussion                                                                                                                         27

5.2 Conclusion                                                                                                                        28

LIST OF TABLES

Table 1: Mineral content in raw Bambara nut and its fermented flour.

Table 2: Fatty acid composition of Bambara groundnut oil.

Table 3: Anti-nutritional factors in raw Bambara groundnut and its fermented flour.

Table 4.1: The mean aerobic bacterial count of the Okpa samples.

Table 4.2: Characterization and identification of bacterial isolates.

Table 4.3: Percentage (%) Occurrence of the bacterial isolates.

CHAPTER ONE

1.0           INTRODUCTION

Several types of microorganisms have been known to affect the quality of food, thereby constituting health hazards when food contaminated with these organisms are consumed. High viable counts often indicate contamination which may be due to contaminated raw materials. It may also be as a result of inappropriate time and exposure during production and/or processing of foods or storage of the food products or the combination of these. Bacteria produce toxic substances while growing in certain foods and bring about food intoxication when consumed. Food infections result from life ingestion of pathogenic organisms especially species of the genus Salmonella which invariably multiply once consumed producing the disease.

The food eaten by man has a direct influence on health. It is therefore an important task for food inspectors, food manufacturers and food handlers to keep food safe from pathogenic microorganisms, especially when such foods are to be consumed without further processing that is ready to eat foods such as Okpa (Frazier and Westhoff, 2004).

Okpa is a popularly known Igbo food which is gaining wide acceptance by people of different ethnic groups and socio-economic classes in our society but has a very short shelf life. Owing to the short shelf life of Okpa, it is produced only in a very small scale and therefore underutilized. It has a shelf life of 24-40 hours after which microbial deterioration sets in.

Food either raw or cooked, hot or chilled that are ready for immediate consumption at the point of sale without further treatment are generally described as ready-to-eat (Tsang, 2002).  The FAO defined street food as ready to eat foods and beverages prepared and/or sold by vendors and hawkers especially in streets and other similar public places.

The emergence of migratory ready-to-eat food vendors call for concern because, while the stationary and ambulatory vendors can exercise some food safety caution in order to produce safe product for their clients, and for fear that a bad product can lead to low patronage by consumers or outright confrontation by customers because the vendor is known by their fixed station/location/routes.  The migratory vendors have no fixed station/location/route.  They move to different routes and locations on highways via commercial motorcycles/vehicles, and their movement is dependent on newly identified failed portions on the highways, repair/construction works on the highways, security posts (check points) accident spots on the highways and possibly they move to different locations/routes to deliberately sale bad products.

Ready-to-eat foods have been reported to be easily available, affordable, provide diverse/variable food source, employment and with a potential for improving food security and nutritional status and general social security. It is however, a veritable source of food borne pathogen (Abdussalam and Kaferstein, 1993; Mensah et al., 2002).

A general observation of our society shows a social pattern characterized by increased mobility due to urbanization, large number of itinerant workers and less family or home centered activities resulting in large percentage of the population depending on ready-to-eat foods for employment and food.  This situation however, has resulted that food sanitary measures and proper food handling have been transferred from individual, families to the food vendors who rarely enforce such practices. There is a general perception that ready to eat vended foods are unsafe, mainly because of the environment under which they are prepared and consumed which exposes the food to numerous potential contaminations. Ready to eat food vendors usually take their food to their customers and therefore operate from such places as bus terminal, market place, industrial sites and other street corners where ready and numerous clients are found. Unfortunately, these locations usually do not meet all food safety requirements. For example, large amounts of garbage accumulate and provide harbourage for insects and other animal pests. The utensils used are also of a nature that may lead to contamination, especially through of leaching of toxic heavy metals or simply due to unsanitary exposure to environment (Nago et al., 2005).

In contrast, concerns over the safety and quality of ready to eat foods have been raised because the vendors lack appropriate basic food safety issues. They often use stands and carts of crude and inefficient construction, running water is not easily accessible, hand and dish washing is done in the same bucket, sometimes without soap. In many cases toilets are not available, thus forcing the vendors to eliminate their body wastes in nearby areas and return to their vending sites without washing their hands. Such conditions and practices are likely to lead to cross-contamination of cooked foods (Mensah et al, 2002).

Microorganisms pose significant contamination risk in food for human consumption and are the chief agent responsible for spoilage of food. The microorganism responsible for food spoilage may be classified into different groups such as the mold, yeast and bacteria. The way in which okpa (Vigna subterranean) which is a ready to eat food is exposed and handled during sales led to the examination of microbiological quality of okpa to evaluate its suitability for consumption.

For the purpose of this study, we shall be based on bacteria only.

1.1       AIM AND OBJECTIVES

The aim of this study is to identify the bacteria of public health importance present in okpa.

SPECIFIC OBJECTIVES

·       Enumeration of bacteria in Okpa.

·       Identification of the isolates.

·       Isolation of the bacteria of public health.

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