ABSTRACT

This study focuses on the isolation and identification of fungi species associated with cocoyam spoilage (Colocasia esculenta). A total of twenty (20) cocoyam samples were selected from Michael Okpara University of Agriculture and National Root Crops Research Institute Umudike, Umuahia Abia State Nigeria farm. A total of three fungi species were isolated using standard microbiological methods. However, their percentage occurrence are Mucor spp 8(53.33%), Fusarium spp 5(33.33%) and Aspergillus spp 2(13.33%). They are pathogenic in nature. In this study, most microorganisms which tend to cause severe rot in cocoyam were observed. The severe rot/spoilage occurrence may be due to improper storage and harvesting of cocoyam and also due to injuries caused after harvest. The above fungi have been found to cause devastating rot blight complex which is a major threat to cocoyam production. But all these can be avoided by proper packaging and handling and use of clean planting equipment and healthy planting materials. Since cocoyam is a food plant consumed by a large population, great care and precaution should be taken in its handling, planting, storage, cooking and preservation.

TABLE OF CONTENTS

Title Page                                                                                                                                i

Certification                                                                                                                            iii

Dedication                                                                                                                              iv

Acknowledgements                                                                                                                v

Table of Contents                                                                                                                   vi

List of Tables                                                                                                                          vii

Abstract                                                                                                                                  ix

CHAPTER ONE

1.0       Introduction                                                                                                                1

1.1       Aim and Objectives                                                                                                    4

CHAPTER TWO

2.0       Literature Review                                                                                                       5

2.1       Scenario of Food Spoilage Worldwide (e.g. Cocoyam)                                             5

2.2       Food Spoilage Microorganisms                                                                                  8

2.2.1    Yeasts                                                                                                                         8

2.2.2    Molds                                                                                                                          10

2.3       Control of Rot and Spoilage of Agricultural Products                                               11

2.3.1    Good Agronomic Practices, Field Sanitation and Store Hygiene                              11

2.3.2    Thermal and Physical Control                                                                                    13

2.4       Biological Control of Rot Organisms                                                                         15

2.4.4    Chemical Control of Rots and their Causal Agents in Postharvest Produce              16

CHAPTER THREE

3.1       Materials and Methods                                                                                               19

3.2       Source/Collection of Samples                                                                                     19

3.3       Materials and Media Used                                                                                         19

3.3.1    Sterilization of Materials                                                                                            19

3.4       Processing of Samples                                                                                                19

3.5       Microbiological Studies                                                                                              20

3.5.1    Preparation and inoculation of samples                                                                     20

3.6       Isolation of Fungi                                                                                                        20

3.7       Subculturing/Purification and Identification of Test Fungi Pathogens                      20

3.8       Identification of Fungal Isolates                                                                                 20

3.8.1    Wet Preparation                                                                                                          21

3.8.2    Colonial Morphology                                                                                                 21

CHAPTER FOUR

4.0       Results                                                                                                                        22

CHAPTER FIVE

5.0       Discussion and Conclusion                                                                                         26

5.1       Discussion                                                                                                                   26

5.2       Conclusion                                                                                                                  29

            References

            Appendix