ABSTRACT

The invitro antimicrobial activities of Moringa oleifera and Hibiscus sabdariffa on tomato spoilage organisms was carried out. Spoiled tomato samples were purchased from four different markets in Umuahia Abia State and calyces of Hibiscus sabdariffa was purchased from the market, and also leaves of Moringa oleifera were gotten fresh from Moringa tree. The tomato samples were examined for the organisms which causes spoilage of tomato and the mean bacterial and fungal counts were gotten. The bacterial isolates were Escherichia coli and Bacillus sp. While the fungal isolate was Rhizopus sp. The colonial count of E. coli isolated from this study was in the range of 5.0 x 105 cfu/g to 1.5 x 106cfu/g while that of Bacillus ranged from 1.2 x03 to 1 5.0 x 104cfu/g. The mean fungal count was in the range of 4.7 x 105 to 2.8 x105. Moringa oliefera and Hibiscus sabdaffla leaf extract were shown to have some degree of antimicrobial properties on the tomato isolates by means of producing a zone of clearance around the growth of the organisms on nutrient plates. The aqueous extract of H. sabdariffa showed maximum activity against Bacillus species with a diameter zone of clearing of 20mm. The ethanol extract of both plants also recorded remarkable activity with zones of inhibition ranging from 6mm to 10mm for the Moringa extracts. The aqeous extract of Hibiscus sabdariffa had the lowest active concentration (MIC) against Rhizopus, E. coli, and Bacillus at 125mg/ml, 62.5mg/ml and 62.5mg/ml respectively. Plants have an almost limitless ability to synthesize aromatic substances. In many cases, these substances serve as plant defence mechanisms against predation by microorganisms.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Tables ix

Abstract x

CHAPTER ONE

INTRODUCTION

1.0 Introduction 1

1.1 Spoilage microorganisms and their adverse effects on fruits and vegetables 2

1.2 Adverse effects 3

1.3 Aim and objectives 4

CHAPTER TWO

LITERATURE REVIEW

2.0 Tomatoes 5

2.1 Importance and uses of tomatoes 5

2.2 Microorganisms associated with tomato spoilage and their effects 6

2.3 Hibiscus sabdariffa (botanical and morphological description) 7

2.4 Phytochemistry of Hibiscus sabdarriffa 8

2.5 Biological and pharmacological activities of H. Sabdariffa 9

2.5.1 Antimicrobial activity of H. Sabdariffa 9

2.5.2 Antioxidant activity of H. Sabdariffa 10

2.5.3 Cancer-preventive activity of H. Sabdariffa 10

2.5.4 Uses of H. Sabdariffa 10

2.6 Moringa  oleifera (botanical and morphological description) 11

2.7 Phytochemistry of M. oleifera 12

2.8 Biological and pharmacological activities of M.  oleifera 13

 2.8.1 Antimicrobial Effects of Moringa  oleifera 13

2.8.2 Antioxidant properties of Moringa  oleifera 13

2.8.3 Anti-cancer properties of M. oleifera 14

2.8.4 Uses of Moringa  oleifera 14

CHAPTER THREE

Materials and Methods 16

3.0 Sample collection 16

3.1 Preparation of extracts 16

3.2 Sterilization of materials 16

3.3 Preparation of media 17

3.4 Isolation and Enumeration of Microorganisms 17

3.4.1 Isolation of bacteria 17

3.4.2 Isolation of fungi 18

3.5 Purification (subculture) of bacterial isolates 18

3.6 Purification of fungal isolates 18

3.7 Characterization and identification of isolates 19

3.7.1 Gram staining 19

3.7.2 Motility test 20

3.8 Biochemical tests         21

3.8.1 Catalase test 21

3.8.2 Coagulase test 21

3.8.3 Oxidase test 21

3.8.4 Urease test 21

3.8.5 Indole test 21

3.8.6 Methyl red- voges proskauer test 21

3.8.7 Citrate utilizatrion test 22

3.8.8 Sugar fermentation tests 22

3.9 Determination of minimum inhibitory concentration 22

3.9.1 Determination of bactericidal concentration (mbc) 23

3.9.2 Antimicrobial susceptibility testing (invitro) 23

CHAPTER FOUR

Results 24

CHAPTER FIVE

Discussion, Conclusion and Recommendation 35

5.0 Discussion 35

5.1 Conclusion 37

5.2 Recommendation 37

References 38