ABSTRACT

Microbial examination of spoilt Avocado fruits was carried out to obtained the causal organism.  A total of 60 avocado from Ogbete Main market and New market Enugu were examined by culturing on nutrient agar and sabourand dextrose agar (SM), for bacteria and fungi causing post – harvest spoilage on the fruits; six bacterial species and six fungal species were isolated. The bacteria include Erwinia SP  (66.7%), Streptococcus sp,  *25%), E. Coli (18.9%) and  staphycoccus sp (33.3%), Pseudomonas sp(20%) and Chromobacterium sp (5%) has the lowest percentage occurrence, Erwinia sp,  Pseudomonas sp and chromobacterium sp were found to be absent in the control.  The fungi species, includes Aspergillus sp  (50%), Pericillium sp  (25%), Fusarium sp  (16.6%), Rhisopus sp  (13.3%), currularia sp (8.3%) and Rhoctorula sp  (3.3%), were also kolated Avocado fruits from Ogbete main market were more contaminated than the avocado form the new market.

TABLE OF CONTENTS

CHAPTER ONE

Introduction

1.1       Background of study

1.2              Statement of problem

1.3              Aim and Objectives of the study

1.4              Hypothesis

1.5              Significance of the study

1.6              Limitation of the study

CHAPTER TWO

Literature review

2.1         The origin of Avocado fruits

2.2        Uses of avocado fruits

2.3        Preservation of avocado fruits

2.4        Ways avocado fruits can be prone to contamination

2.5        Microbial spoilage of avocado fruit

2.6        Control of bacterial and other disease of avocado fruits and fruits products

2.7        Some biochemical test for bacterial isolates

CHAPTER THREE

Materials and methods

3.1       Sample collection

3.2              Sterilization of media an material used

3.3              Preparation of media

3.4              Bacteria and fungi isolate from avocado fruits

3.5              Bacterial isolation and identification

3.6              Fungal isolation and identification

3.7              Lactophenole blue staining technique for fungi isolates

3.8              Staining techniques for bacteria isolates grains stain

3.9              Biochemical test for identification of bacteria isolates

CHAPTER FOUR

Results and discussion

4.1       Bacterial Examination

4.2              Fungi, examination

CHAPTER FIVE

Conclusion and recommendation

5.1       Conclusions

5.2              Recommendation

Reference

LIST OF TABLE

Table I:            Bacterial isolated and their frequencies

Table 2:           Fungi isolated and their frequencies

Table 3:           Sources of collection of the fruit and Bacteria isolate

Table 4:           Sources of collection of the fruits and fungi isolates

LIST OF FIGURES

Fig. 1:              Rate of occurrence of fungi

Fig. 2:              Rate of occurrence of bacteria

Fig. 3:              Fungi isolates according to sources

Fig. 4:              Bacteria isolates according to source.

CHAPTER ONE

1.0              INTRODUCTION

1.1       BACKGROUND  OF STUDY

The Avocado pear, Persea   Americana is a tropical and sub tropical  fruit tree, originated in central America or adjoining regions of North or South America.  It has now spread to much of the near tropical world.  The avocado is limited especially by its climatic requirements, with their race differences.  It is also highly susceptible to drought injury.  But excess soil moisture is equally fatal, encouraging the dread phytophthora root rot in most of the world, and where  the fungus is unknown. Despite the high water activity of  most fruits, the how PH leads to their spoilage being dominated by fungi, both yeast and moulds.  Other common diseases of pears include the black spot or scab caused by as comycetes

            Avocado fruits has being estimated that one fourth of all produced harvested is no consumed before spoilage (Salulche, 1974), spoilage of fresh fruits usually occurs during storage and transport and while wacting to be processed unlike many other foods fruits after picking and before processing are ‘a live’ of the products plus the normal ripering process complicate an independent discussion of the microbiological spoilage problems are really market diseases of these products:

            Shape, varies from slightly obligate to highly elongate, an intermediate oval or pear shape is preferred.  Yellow to purple or black.

            The composition of the fruit influences the likely type of spoilage.  thus bacteria soft rot is widespread for the most part among the fruits is limited to those that are not highly acid.  Because most fruits are somewhat acid are fairly dry at the surface, and are deficient in B vitamins, mold are the most common causes of spoilage.  The compositions too, must determine the particular kind of molds most likely to grow, thus avocado support a large, variety of fungal spoilage organisms and other kinds comparatively few.

1.2       STATEMENT OF PROBLEM

Micro-organisms are known to destroy fruits, thereby reducing the quantity for consumption and the profits desirable from fruits such as avocado.  Many spot are noticed on pears which do change the taste when consumed.

            Bacteria and fungi are harmful and useful living organisms.  The spoilage of most fruits is always associated with  bactera and fungi, many diseses of plants are associated with bacteria and fungi (Micro-organisms)

            The adverse effect of bacteria in plants and fruits has resulted in shortage of avocado fruits for consumption. Revenue is lost by farmers and industries that uses avocado fruits as a raw materials for fruit juice due to the spoilage caused by micro-organisms.

1.3       AIM AND OBJECTIVES OF THE STUDY

Microbial examination of spoilt avocado fruits

To isolate and identify how micro-organism destroy avocado so as to guide producer  and farmers on how to manage the fruits

To isolate and identify it those micro-organisms are responsible for the spoilage

To compare the extent of spoilage in the area of colelction (tree) with that of market

1.4       HYPOTHESIS

HO:     Microbial organisms do not cause spoilage of avocado at either in the field or during exposure for sale.

Hg       = Microorganisms (Fungi and Bacteria) are responsible for avocado spoilage.

1.5              SIGNIFICANCE OF THE STUDY

This study will be useful to farmers, fruit juice industries and consumers of avocado fruits. T he outcome of this research will guide users of avocado fruit on the best method of preserving to avoid spoilage, the research work also will add to the literature and information existing about avocado for student and companies that uses avocado as raw materials for the production of fruit juice.