ABSTRACT

The study evaluated the occurrence of biodeteriogens in harvested tomato fruits and their antimicrobial sensitivity. A total of Twenty (20) Tomato fruit samples were purchased at guided random from five different markets (Ahieke, Orieugba, Ndioru, Umuariga and Gate 6 market) in Umuahia, Abia State. The Tomatoes were cultured on Sabouraud Dextrose Agar, Nutrient Agar (NA), and MacConkey Agar (MAC), using a pour plate technique. From the result obtained, a total of five (5) bacterial species, and three (3) fungal species and one (1) yeast species isolated. The biochemical, Morphological and cultural features revealed the bacterial and fungal isolates to be Escherichia coli, Staphylococcus aureus, Bacillussubtilis, Serratia marcesens, Proteusmirabilis, Aspergillus niger, Fusarium oxysporum, Rhizopus stolonifer and Rhodotorula spp. Among the five major markets investigated however within Umuahia metropolis, Gate 6 market had the highest bacteria at 2.8x105. In the decayed tomato samples assessed, it was observed that Escherichia coli were the most frequently occurring isolates with a high percentage occurrence of 6(21.4%). The occurrence of Escherichia coli that is usually associated with faecal matter also affirmed poor hygiene in the markets. However, there were wide variations in the fungi population, with Aspergillus niger 4(14.3%) and Rhizopus stolonifer 4(14.3%) being most predominant and occurring isolates, followed by Rhodotorula sp., 2(7.1%) and Fusarium oxysporum 1(3.6%). It was also recorded in this study that Aspergillus niger and Rhizopus stolonifer dominated and had the highest percentage of occurrence over other fungal species.

TABLE OF CONTENTS

Title Page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1

1.1 Aim and Objectives 4

CHAPTER TWO

2.0 Literature Review 5

2.1 Brief Description of Tomato Fruit 5

2.2 Antibiotic Sensitivity of Bacterial and Fungal Isolates from Tomato 

(Solanum Lycopersicum) Fruit 6

2.3 Control of E. coli and Spoilage Microorganisms in Tomato Sauce and Paste 

Using a Synergistic Antimicrobial Formula 8

2.4 Isolation and Identification of Fungi Associated With Postharvest 

Decay of Lycopersicum EsculentumSold in Abakaliki, Nigeria 10

2.5 Isolation of Microorganisms Associated With Deterioration of Tomato 

(Lycopersicon Esculentum) and Pawpaw (Carica Papaya) Fruits 11

CHAPTER THREE

3.0 Materials and Methods 14

3.2 Source/Sample Collection 14

3.3 Materials and Media Used 14

3.3.1 Sterilization of Materials 14

3.4 Processing of Samples 14

3.5 Microbiological Studies 15

3.5.1 Inoculation and Enumeration of Microorganisms 15

3.6 Microbial Characterization and Identification 15

3.6.1 Identification of Bacterial Isolates 15

3.6.1.1 Gram Staining 15

3.6.2 Biochemical Tests 16

3.6.2.1 Indole Test 16

3.6.2.2 Carbohydrate Utilization Analysis 16

3.6.2.3 Catalase Test 16

3.6.2.4 Oxidase Test 16

3.6.2.5 Coagulase Test 17

3.6.2.6 Citrate Utilization Test 17

3.6.2.7 Motility Test 17

3.6.2.8 Methyl Red Test 17

3.7 Spore Staining 17

3.8 Subculturing/Purification and Identification of Test Fungi Species 17

3.9 Identification of Fungal Isolates 18

3.9.1 Wet Preparation 18

3.9.2 Colonial Morphology 18

3.10 Antimicrobial Susceptibility Testing 18

CHAPTER FOUR

4.0 Results 20

CHAPTER FIVE

5.0 Discussion and Conclusion 27

5.1 Discussion 27

5.2 Conclusion 30

References