ABSTRACT

This study investigated the microorganisms associated with the spoilage of tomatoes (Lycopersicon esculentum) fruit obtained from five markets namely: Orie Ugba, Ubani, Nkwoegwu, Ubakala and Ogwumabiri markets in Umuahia, Abia State, Nigeria. A total of five species of bacteria isolated and identified are: Staphylococcus, Proteus, Bacillus, Escherichia, and Pseudomonas species. The most prevalent bacterial isolate was Staphylococcus spp. with 100% and was found in all the samples while Proteus spp. was the least prevalent isolate with 40%. The fungal isolates were Aspergillus, Penicillium, Saccharomyces, Rhizopus, Mucor and Botrytis species. The most prevalent among the fungal isolates was Saccharomyces with 100% and was also found in fruit samples from all the markets. The mean bacterial load ranges were 17.33 x104 Cfu/g – 38.33 x104 Cfu/g for Orie Ugba market; 25.33 x104 Cfu/g for Ubani market; 40.00 x104 Cfu/g – 93.67 x104 for Nkwoegwu market; 21.33 x104 Cfu/g – 47.33 x104 Cfu/g for Ogwumabiri market. The mean fungal load ranges were 4.00 x102 Cfu/g – 8.33 x102 Cfu/g for Orie Ugba market; 3.67 x102 Cfu/g – 9.67 x102 Cfu/g for Ubani market; 3.67 x102 Cfu/g – 10.67 x102 Cfu/g for Nkwoegwu market; 7.00 x102 Cfu/g – 9.67 x102 Cfu/g for Ubakala market and 7.00 x102 Cfu/g – 11.67 x102 Cfu/g for Ogwumabiri market. Based on this research work, it can be agreed that the intake of spoilt tomatoes could be dangerous, since these organisms produce spores and toxins that could cause severe food poisoning that will result in fatal outcome. Moreso, fruit storage room kept at high sanitary conditions, treatment of fruits with antimicrobial agents, as well as some forms of refrigeration is necessary to increase shelf-life and reduce the rise of microbial toxins which are disastrous to human health.    

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 Aims and Objective of Study - - - - - - - 2

CHAPTER TWO

2.0 LITERATURE REVIEW - - - - - - - 3

2.1 Brief history and Distribution of Tomato Fruit - - - - 4

2.2 Varieties of Tomato Fruit - - - - - - - 4

2.3 Disease Symptoms due to Fungi and Bacteria in Tomato - - - 6

2.3.1 Bacterial Diseases - - - - - - - - 6

2.3.1.1 Bacterial Spot - - - - - - - - - 6

2.3.1.2 Bacterial canker: - - - - - - - - 6

2.3.2 Fungal Diseases - - - - - - - - 7

2.3.2.1 Sour Rot - - - - - - - - - 7

2.3.2.2 Rhizopus Rot: - - - - - - - - - 7

2.3.2.3 Buckeye Rot - - - - - - - - - 8

2.3.2.4 Black Mold - - - - - - - - - 8

2.4 Physiological Disorders of Tomato - - - - - - 8

2.5 Control of Postharvest Diseases and Losses of Tomato - - - 9

2.5.1 Biological Control - - - - - - - - 9

2.5.2 Chemical Control: - - - - - - - - 10

2.5.3 Physical methods: - - - - - - - - 11

2.5.3.1 Heat Treatment: - - - - - - - - 11

2.5.3.2 Waxing and coating - - - - - - - - 12

2.6 Mineral Nutrition of Tomato - - - - - - - 12

2.6.0 Responses to specific nutrients and nutrient ratios - - - - 13

2.6.1 Nitrogen - - - - - - - - - 13

2.6.2 Phosphorous - - - - - - - - - 14

2.6.3 Potassium - - - - - - - - - 14

2.6.4 Calcium - - - - - - - - - 15

2.6.5 Magnesium - - - - - - - - - 16

2.6.6 Iron - - - - - - - - - - 16

2.6.7 Manganese - - - - - - - - - 17

2.6.8 Zinc - - - - - - - - - - 17

2.6.9 Copper - - - - - - - - - - 18

2.6.10 Molybdenum - - - - - - - - - 18

2.7 Medicinal uses of Tomato - - - - - - - 19

2.8 Health Benefits of Tomato - - - - - - - 21

2.9 Spoilage of Tomatoes - - - - - - - - 27

2.10 Prevention of tomato spoilage - - - - - - 27

CHAPTER THREE

3.0 MATERIALS AND METHODS

3.1 Source of Materials - - - - - - - - 29

3.2 Sample and Media Preparation- - - - - - - 29

3.2.1 Sample and Sampling - - - - - - - - 29

3.2.2 Media Preparation - - - - - - - - 29

3.3 Isolation of Microorganism and Determination Load - - - 30

3.3.1 Spread Plate Technique - - - - - - - 30

3.3.2 Direct Placement Technique - - - - - - - 31

3.4 Purification of Pure Isolates - - - - - - - 31

3.5 Characterization and Identification of Isolates - - - - 32

3.5.1 Characterization of Fungi Isolates - - - - - - 32

3.5.2 Characterization of Bacteria - - - - - - - 32

CHAPTER FOUR

4.0 RESULTS - - - - - - - - - 38

CHAPTER FIVE

5.1 Discussion - - - - - - - - - 50

5.2 Conclusion - - - - - - - - - 51

5.3 Recommendations - - - - - - - - 52

References - - - - - - - - - 53

Appendix

LIST OF TABLES

Table Title Page

1 Microbial  load of spoilt tomatoes. 39

2 Occurrence of bacterial isolates in spoilt tomatoes 41

3 Occurrence of Fungal isolates in spoilt tomatoes 43

4 Occurrence of Fungal Isolate in Spoilt Tomatoes 44

5 Occurrence of Bacterial Isolate in Spoilt Tomatoes 45

6 Colonial and Morphological Characteristics of Fungal Isolates 46

7A Characterization and Identification of Bacterial Isolates 47

7B Characterization and Identification of Bacterial Isolate 48

7C Characterization and identification of bacterial isolate 49