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
Title page
Certification
Dedication
Acknowledgement
List of Tables
List of figures
Abstract
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
1.6 LIMITATION
OF THE STUDY
There are
many or different type of microorganism that causes spoilage in avocado fruit
or fruits in general, focus is made only on fungi and bacterial because they
are the major organisms associated with spoilage in avocado fruits.
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