Microorganisms Associated With Deteriorated Tomatoes

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