ABSTRACT
Investigation of microorganism associated with the spoilage of banana and pawpaw were carried out. The isolation of bacteria from the banana and pawpaw was carried out on Nutrient agar, MacConkey agar and salmonella shigella agar while that of fungi was on Sabouraud Dextrose agar. A total of seven (7) bacteria and two (2) fungi isolates were obtained. The bacteria isolates were Escherichia coli, Staphylococcus aureus, Pseudomonas spp, Klebsiella spp, Enterococcus spp, Salmonalla spp and Shigella spp. The fungal isolates were Aspergillus flavus and Aspergillus niger The highest occurring bacterium was Escherichia coli (40%),and the least were Salmonella and Shigella spp (10%) Staphylococcus aureus (30%), Pseudomonas spp (25%), Klebsiella spp, (25%), Enterococcus spp (20%). The highest fungus was Aspergillus flavus (25%), and the least was Aspergillus niger (15%). The result showed that pawpaw and banana from Ndioru market has the highest bacteria count of 6.6 x102cfu/ml, 5.3 x 104cfu/ml and fungal count of 2.9 x 104cfu/ml. The comparison showed that all the bacterial and fungal isolates associated with the spoilage are present in the pawpaw except Shigella spp and Aspergillus niger which were absent in the banana. It also showed that the bacteria isolate were most predominant compared to the fungal isolates. The presence of these bacteria and fungi present a health risk factor to people who consume fruits without washing. Consumers should avoid consumption of spoilt fruits to avoid health implications that may lead to death.
TABLE OF CONTENTS
Title Pages
Title Page i
Certification ii
Dedication iii
Acknowledgement iv
Table of Contents v
List of Tables vii
Abstract viii
CHAPTER ONE: INTRODUCTION
1.1 Preamble 1
1.2 Aim and Objectives 3
CHAPTER TWO: LITERATURE REVIEW
2.1 Banana (Musa species) 4
2.1.1 Health
benefits of banana 5
2.2 Pawpaw (Carica papaya) 10
2.2.1 Cultivation 11
2.1.2 Propagation 12
2.1.3 Habitat restoration 12
2.1.4 Fruits 13
2.1.5 Health benefits of pawpaw 13
2.3 Molds 18
2.5 Bacteria 19
2.6 Bacteria Spoilage of Banana and Pawpaw 20
2.7 Fungal Spoilage of Banana and Pawpaw
Fruits 21
2.7.1 Other fungal spoilage of banana 22
2.8 Control
of Bacteria and Fungi Disease of Banana and Pawpaw Fruits 23
CHAPTER THREE: MATERIALS
AND METHODS
3.1 Materials 25
3.2 Sample Collections 25
3.3 Preparation of Media 25
3.4 Enumeration of Fungi and Bacteria 25
3.5 Purification of Bacteria Isolate 26
3.6 Purification of Fungal Isolates 26
3.7 Characterization and Identification of
Bacteria Isolates 26
3.7.1 Gram staining technique 26
3.7.2 Motility test 27
3.7.3 Catalase test 27
3.7.4 Coagulase test 27
3.7.5 Indole test 28
3.7.6 Citrate test 28
3.7.7 Sugar fermentation 28
CHAPTER FOUR: RESULTS 29
CHAPTER FIVE: DISCUSSION, CONCLUSION AND
RECOMMENDATIONS
5.1 Discussion 35
5.2 Conclusion 37
5.3 Recommendations 38
References 39
LIST
OF TABLE
Table Title Pages
1 Isolation and identification of
bacteria 30
2 Cultural and morphological
identification of fungi 31
3 Percentage
of occurrence of microorganisms isolated from pawpaw
and
banana sold at five(5) different markets in Umuahia 32
4 Microbial counts of
pawpaw and banana samples in cfu/ml 33
5 Comparison
of microorganism isolated from pawpaw
and
banana sold in five (5) different markets in Umuahia. 34
CHAPTER 1
INTRODUCTION
1.1 PREAMBLE
Food spoilage refers to the various changes in
which the food becomes less palatable or even toxic to consumers. These changes
may be accompanied by alterations in taste, smell, appearance or texture
.Numerous microbial defects of agricultural crops are characterized by the type
of microorganism responsible for their deterioration (Akinmusire, 2011).
A fruit is the edible part of a mature ovary of
a flowering plant. It is usually eater raw. When matured, they may be either
fleshy or dry. Fleshy fruits are further classified into berry (orange,
tomatoes, pineapple, pawpaw, and banana), drupes (plume, coconut, almond, cherry)
and plumes such as apple and pear. The dry fruits, unlike the fleshy fruits
which have unlayered pericarpe are
classified in to
dehiscent (pod, follicle and capsule) and indehiscent
fruits like achene, samara, cashew etc (Jay, 2000).
Fruits and vegetables are vital sources of
nutrient to human beings. They give the body the necessary vitamins, fats, minerals
and oil in the right proportion for human growth and development. Fruits and
vegetables are however, have serious changes to their existence. These incline
changes in climatic conditions, pest and microbial attack. Over the years,
there has been the need to isolate the microorganisms associated with the
spoilage as a way of finding a means of controlling it (Akinyele and Akinkunmi,
2012).
Susceptibility of fruits and vegetables is
largely due to differential chemical composition such as Ph and moisture
contents are associated with greater predisposition to microbial
spoilage. The occurrence of fungal spoilage of fruits is also recognized as a
source of potential health hazard to man and animals. This is due to their
production of my mycotoxins (naturally occurring toxic chemicals often of
aromatic structure) which are capable of producing aflatoxins in man following
inhalation or ingestion.
Banana and Pawpaw are botanically called Musa sapientum and Carica papaya. Their
spoilage is due to biotic factors and being that they are perishable fruits.
Pawpaw fruit can be fleshly eaten or cooked. It can be used in the preparation
of jellies, juice and jams. It has a great application in the preparation of
fruit salad and desert (Mitra, 1997). Banana contains about 75% water, 23%
carbohydrate and 3% protein. Banana without the peel is a good source of
vitamins, potassium and fiber. Banana fruit may be eaten raw or cooked. The
fruit can also be processed for a number of products. Ripped fruit can be pulped
for puree for a variety of products including ice cream, yoghurt, cake bread, m
Green (unripe banana) can be fried and sliced as chips.
Banana leaves are not eaten but maybe used for
wrapping food in cooling. The banana foliage and pseudo stem are used as cattle
feed during dry period in some banana producing areas. Banana
has a good source of energy but need to be supplemented with proteins.
These fruits are usually displayed on benches
and in baskets for prospective customers in the open market until sold, thereby
exposing them to further microbial infection beside those associated with these
whole fruit surface and those from adjacent infected fruits
(Baiyewu et al., 2007).
In developing countries, post
harvest deterioration are often more severe due to inadequate storage and
transportation facilities. Microbial fruit infection may occur during the
growth season, harvesting, handling, transport and post harvest storage and
marketing conditions, or after purchasing by the consumer. Fruits contain high
levels sugar and nutrient elements and their low pH values makes them
particularly desirable to fungi decay (Singh and Sharma, 2007). Studies by
Li-cohen and Bruhiri (2002) shows that fungi can survive and grow on fresh
produce and that the nutrient content (carbohydrate, protein and fat) of fresh
produce support pathogens.
Fruits are affected by a wide array of
microorganisms causing its decay. Spoilage microorganisms can be introduced to
the crop on the seed itself, during crop growth in the field, during harvesting
and post harvest handling or during harvest and distribution (loading and
offloading) (Barth et al.,
2009).
Those type of soil born spoilage microbes that
occur on produce are the same spoilage microorganisms that are present oh
harvesting equipments, on handling equipment in the packaging house, in the
storage facility and on food contact surfaces throughout the distribution
chain.
Therefore, early intervention measures during
crop development and harvesting through the -use of Good Agricultural Practices
(GAP) will provide dramatic reduction in the yield loss due to deterioration at
all subsequent steps in the food (Barth et al., 2009).
1.2 AIM
AND OBJECTIVES
1.
To determine the bacteria present in the
spoilage of banana and pawpaw.
2.
To determine the fungi present in the spoilage
of banana and pawpaw.
3.
To compare the microorganisms associated with
the spoilage of banana and pawpaw.
Login To Comment