ABSTRACT

This study evaluated the microbiological quality of fruits sold in Umuahia metropolis. A total of fifteen (15) sliced fruit samples consisting of 5 watermelon, 5 pawpaw and 5 pineapples were collected from five different markets. The samples were cultured on Nutrient Agar Medium, MacConkey Agar, and Sabauroud Dextrose Agar using pour plate techniques. A total of nineteen (19) bacteria were isolated and identified using morphological characteristics, pigmentation on media, microscopy, biochemical and sugar fermentation methods. The bacteria were Bacillus species, Escherichia coli, Staphylococcus aurues, Proteus species and Micrococcus species while the fungal isolates were Aspergillus niger, Aspergillus fumigatus and Rhizopus stolonifer. Ndioru had the highest aerobic plate count at 3.1x105, followed by Unuariaga (3.0x105), Orieugba (2.9x105), Gate six (2.4x105), while the least aerobic plate count was recorded at Ahieke (1.9x105) in that order. The total coliform plate count investigated reveals that Orieugba had the highest coliform plate count at (3.5 x105) while Ndioru and Umuariaga had the least total coliform plate count of (2.4 x105). The total viable fungal plate count reveals Gate six as having the highest viable fungi count at (4.5 x105), while Ndioru has the least viable fungi count at 2.3x105. The percentage occurrence and distribution of bacterial isolates revealed that Escherichia coli occurred most frequently with percentage occurrence of 6(20.0%) followed by Bacillus spp  and  Proteus spp at 4(13.3%) each, Staphylococcus aureus 3(10.0%), and Micrococcus spp 2(6.6%) respectively. Aspergillus niger was the most predominant with 5(16.6%), followed by Aspergillus fumigatus 4(13.3%) while the least was Rhizopus stolonifer at 2(6.6%).This study also revealed that Staphylococcus aureus showed high level of susceptibility to Amoxil, Erythromycin and Levofloxacin. Bacillus spp showed high level of resistance to Ciprofloxacin, Amoxill and Chloramphenicol while Escherichia coli showed high resistance to Norfloxacin. The presence of these microorganisms in the fruit juices is of public health significance. Therefore, regular monitoring of the quality of commercially available fruit juices for human consumption is recommended to avoid outbreak of food borne illness resulting from the organisms encountered in this study.

TABLE OF CONTENTS

Title Page   i

Certification ii

Dedication iii

Acknowledgements 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 4

2.1 Microbiology Of Polyethylene-Packaged Sliced Watermelon 

(Citrullus Lanatus) Sold By Street Vendors in Nigeria 4

2.2 Microbiological Quality of Pre-Cut Fruits On Sale in Retail 

Outlets in Nigeria 5

2.3 Microbiological Quality of Sliced Fresh Fruits Sold In Bida Nigeria 6

2.4 Bacterial Pathogens Associated with Fruit Contamination 7

2.4.1 Campylobacter 7

2.4.2 Pathogenic Escherichia coli 8

2.4.3 Salmonella spp 8

2.4.4 Shigella spp 9

2.4.5 Staphylococcus 10

2.4.6 Vibrio 10

2.4.7 Listeria monocytogenes 11

2.4.8 Sporeformers 11

2.5 Sources of Contamination 12

2.5.1 Production Environment 12

2.5.2 Postharvest Handling 13

2.5.3 Human Hygiene 14

2.6 Pathogen Prevention 15

2.6.1 Processing Strategies 15

2.6.2 Handling Parameters 17

2.6.3 Alternative Technologies 18

CHAPTER THREE

3.0 Materials and Methods 20

3.1 Study Area 20

3.2 Materials and Reagents 20

3.3 Collection of Samples 20

3.4 Sterilization of Materials 21

3.5 Preparation of Culture Media 21

3.6 Inoculation and Isolation 21

3.7 Purification of Isolates 22

3.8 Identification of the Isolates 22

3.9 Gram Staining 22

3.10 Biochemical Test 23

3.10.1 Catalase Test 23

3.10.2 Indole Test 23

3.10.3 Citrate Utilization Test 23

3.10.4 Hydrogen Sulphide (H2S) Production Test 24

3.10.5 Starch Hydrolysis 24

3.10.6 Motility, Indole, Urease (MIU) 24

3.10.7 Coagulase Test 25

3.10.8 Oxidase Test 25

3.11 Identification of Fungal Isolates 25

3.11.1 Colonial Morphology 25

3.11.2 Yeast Viability Staining 26

CHAPTER FOUR

4.0 Results 27

CHAPTER FIVE

5.0 Discussion and Conclusion 34

5.1 Discussion 34

5.2 Conclusion and Recommendation 37

REFERENCES