MICROBIAL QUALITIES OF FRUITS SOLD IN UMUAHIA METROPOLIS

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