ABSTRACT
The comparative study of microorganisms associated with the spoilage
of banana. “Banana is a general term embracing a number of species or
hybrid in the genus musa, family bacteria organisms, small pieces of
decayed tissue from the leading edge of the lesion was transferred, by
means of sterile techniques, to the SDA contained in covered dishes and
incubated at room temperature (28-370c). The fungal and bacterial
growth visible within 2-7 days. Each observed fungal and bacterial
growth based on their morphological and cultural microscopic
examination and this microscopic examination was done using the
lactophenol staining technique. Some organisms like Erwinia species
has been incriminated as pathogen, saprophyte or constituent of epiphyic
flora of plants.
TABLE OF CONTENTS
CHAPTER ONE
1.1 INTRODUCTION
1.2 AIM AND OBJECTIVE
1.3 SIGNIFICANCE OF STDY
1.4 STATEMENT OF PROBLEM
1.5 LIMITATION
1.6 HYPOTHESIS
CHAPTER TWO
2.0 LITERATURE REVIEW
2.2 MOLDS
2.3 YEAST
2.4 BACTERIA
2.5 BACTERIAL SPOILAGE OF BANANA
2.6 FUNGAL SPOILAGE OF BANANA
2.7 OTHER FUNGAL SPOILAGE OF BANANA
2.8 CONTROL OF BACTERIAL AND FUNGAL DISEASES
CHAPTER THREE
3.0 MATERIALS AND METHOD
3.1 STERILIZATION OF MATERIALS AND MEDIA USED
3.2 PREPARATION OF SABORAUD DEXTTROS AGAR (SDA)
3.3 PREPARATION OF NUTRIENT AGAR
3.4 BACTERIAL/FUNGAL ISOLATION BANANA FRUIT
3.5 BACTERIAL ISOLATION AND IDENTIFICATION
3.6 FUNGAL ISOLAATION AND IDENTIFICATION
3.7 STAININMG TECHNIQUE FOR BACTERIAL ISOLATES
3.8 ISOLATION OF YEATS AND MOLD
CHAPTER FOUR
4.0 RESULTS
4.1 BACTERIAL EXAMINATION
4.2 FUNGI EXAMINATION
CHAPTER FIVE
5.0 DISCUSSION
CONCLUSION
RECOMMENDATION
REFERENCES
LIST OF TABLES
TABLE I: BIOCHEMICAL ISOLATES FOR BACTERIAL
TABLE II: FUNGI ISOLATE
TABLE III: BIOCHEMICAL TEST FOR YEAST ISOLATED
TABLE IV: SOURCES OF COLLECTION OF THE FRUITS
TABLE V: ORGANISMS ISOLATED AND THEIR FREQUENCIES
LIST OF FIGURES
FIGURE I: HOW ERWINIA SPECIE IS THE HIGHEST OCCURRENCE
FIGURE II: HOW ASPERFILLUS SPECIE IS THE HIGHEST OCCURRENCE
FIGURE III: THE LEAST OCCURRENCE IS CHROMOBACTERIUM SPECIE
FIGURE IV: THE HIGHEST AND ATHE LEAST OCCURENCES WERE ASPERGILLUS SPECIE AND RHODOTORULA SPECXIE
FIGURE V: THE GRAPHICAL REPRESENTATION OF THE FREQUENCY OF OCCURRENCE OF THE MICROORGANISM FOUND IN THE TESTED BANANA.
FIGURE VI: SHOWS THE FREQUENCY OF OCCURRENCE OF THE MICRO-ORGANISM FOUND IN THE SPOILT BANANA FRUITS.
CHAPTER ONE
1.1 INTRODUCTION
Banana may be defined as a personal seed plant that produces an
edible fruits, usually seedless, belong to the species M. acuminata, or
are hybrids M. acuminata, M. balbisnna. They are perennial herbs with
long, the bases of these leaves (petioles) remain tightyly fused and
form the trunk (Pseudostem) of a plant 2-9m (6-30-ft) in height (Ploetz,
1994),
“Banana” is a general term embracing a number of species
or hybrids in the genus musa, family musceae. In some areas of the world
bananas are grown only as ornamental plants or for fiber.
It is found in tropical regions. The banana is
monocarpic, flowering and setting fruit once before sit dies. The
inflorescence protective flag leaf. The flower stalk of most banana
varieties is positively geotropic and bends from the vertical until its
stip points towards vertical flower stalks are from 30 – 90 cm (1-3ft)
along, tapered and covered in a sheath of over- lapparing bracks the
flower are parthenogenic (self-fertile). And occur in group of 12-20
beneath the bracks.
At first, individual fruiots called fingers, make up the
groups (hands) which are arranged in a spiral around the flower stalk,
forming a bunch.
At fruit set, a healthy banana plant will have 8-12
leaves, fruits mature in 60-100 days after flowers first appears
depending on the season and cultivan. New banana plants arise as
suckers from an underground rhizone. As old planted die and new sucher
are formed the rhizome expands and is called a mat. Banana are
propagated by suckens, pieces of the Bluzome and by tissue culture
(Ploetz 1994)
USES
Bananas contain about 74% waterm 23% carbohydrate, 1% protein and 0.5
%. A 4 – ounce banana without the peel is a good source of vitamin
Bb, Potassium, and fiber.
Banana fruit may be eaten raw or as a cooked vegetable. The fruit can also be processed for a number of food products.
Ripe fruits can be pulped for puree for in a variety of
products including ice cream, yoghurt, cake, bread, nectar, and baby
food. Ripe banabas can be dried and eaten, or sliced canned with syrup,
and used in bakery products, fruits salads and stoppings. Green
(unripened) bananas can be sliced and fried as chips. Whole green fruits
can also be dried and ground into flour. Vinegar and alcoholic
beverages can be made from fermented ripe bananas. Other parts of the
banana plant are consumed besides the fruits. The heart of the growing
pseudostem is eaten in India. In Southeast Asia, the male bud is eaten
as a boiled vegetable.
The banana leaves are not eaten but may be used for
wrapping food in cooling. The banana foliage and pseudostems are used as
cattle feed during dry periods in some banana producing areas. Culled
bananas are used sto feed cattle and hogs. Bananas are a good energy
source but need to be supplemented with protein. But not all
micro-organisms associateeed with fruits are harmless”. This includes
the lactic acid bacteria, coryne forms, pseudomonads, xanthomonads
micrococci, amny fungi and coliforms. These microorganisms do play an
important role in the spoilage of food and dictate the shelf life of
fresh fruits. Most healthy raw produce will have on them anywhere from
a few thousand to millions of miucroorganisms per gram. The presence
of many of these microorganisms is a concern for causing product
spoilage.
Food spoilage is a major problems in all societies
especially fruits, because they provide nutrients for us, also are
excellent environment for the growth of micro-organisms. Microbial
growth as well as spoilage is controlled by factor related to the food
itself or intrinsic factor and also to theenvironment where the food is
being stored or what are described as extrinsic factors. Food
composition is critical intrinsic factor that influences microbial
growth, if a food consider primarily of carbohydrates, spoilage does
not result in major odours. Thus, foods such as some fruits e.g. banana
show spoilage by fungal growth. Also, PH of a food also is critical
because a low PH a food also is critical because a low PH favours the
growth of yeasts and mold. This is the case in banana fruit because it
has PH of 2-5 physical structure of a food also can affected the course
and extension of spoilage. Banana fruits has outer skin (peels) that
project them from spoilage.
Often, spoilage micro-organisms have specialized enzymes
that help them weaken and penetrate protective peels, especially after
the fruits has been bruised. Temperature and relative humidity are
important extrinsic factors in determining whether a fruit (banana) will
spoil. At higher relative humilities, microbial growth is initiated
more rapidly even at lower temperatures.
The atmosphere in which the fruit is stored is also
important as this plays a crucial role in its spoilage. Because fruits
are such excellent sources of nutrients, If the intrinsic and extrinsic
conditions are appropriate, micro-organisms grow rapidly and make what
once was an attractive and appealing fruits into a sour, foul-smelling
or fungus – covered mass suitable only for the garbage car.
Microbial spoilage in Banana can lead to visible challenges, including a variety of colours caused by spoilage organisms.
Bacteria do not seem important in the initial spoilage
of whole fruits like banana instead such spoilage often is initiated
by molds. These organisms have enzymes that contribute to the weakening
and penetration of the protective outer skin. Many microorganisms have
been isolated from banana, actually spoilt banana. These
micro-organisms have been associated with moko disease, or moko de
Guineo, or marchites bacteriana, is caused by the bacterium, pseudomonas
solanacearum, resulting in internal decay. It has become one of the
western hemisphere and has seriously reduced production in the leading
area as of Colombia. It attacks Heliconia species as well. It is
transmitted by insects, machetes and with the roots of sick plants.
There are said to be 4 different types transmitted by different means.
Efforts at control include covering the male and bud with plastic to
prevent insects from visiting its mucilaginous excretion, debudding,
disinfecting of cutting tools with formalde hyde in water 1:3,
disinfection of planning material; disposal of infected fruits and
plant parts: infection of herbicides into seemingly healthy neighbouring
plants. if The organism is vriant SFR, all adjacent plants. If the
organism is variant SFR, all adjacent plants within a radius replanted
for 10 to 12 months for this variant persists in the soil that long. If
it is variant B, the plants within 32.8 ft (10m) must bee injected and
the area not replanted for 18 months.
In either case the soil must be kept clear of broad
leaved weeds that may serve as hosts. In Colombia, there are 12 species
of weeds that serve as hosts or “carriers:” but only 4 of these are
themselves susceptible to the disease. Crop rotation is sometimes
resorted to the only sure, defense is to plant resistant cultivans.
Such as the ‘pelipita’ plantain.
Black-end arises from infection by the fungus arises from
infectrion by the fungus Glocosporium musarum, of which Glomerella
cingulata is the perfect form. It causes authracuose on the plant and
attacks the stalk and stalk – end of the fruits forming dark, sunken
lesions on the peel, soon penetrating the fresh and developing dark,
watery, soft area in severe cases, the entire skin turns black and the
flesh rats. Very young fruits shrived and mummify. This fungus is often
responsible for the rotting of bananas in storage. Immersing the green
fruits in hot water. 131of (55oc) for 2 minutes before ripening
greatly, reduces spoilage.
Sigar-tip rot, or cigan-end disease, stachylidium
(verticillium) theobromae begins in the flowers and extends to the tips
of the fruits and turns sthem darks the peel darknens, the flesh becomes
Fibrous. One remedy is to cut off withered flowers as soon as the
fruits are formed and apply copper fungicides to the cut surfaces.
Unlike most other fruits, banana develop their best eating quantity
after they are harvested. This allows bananas to be shipped great
distances. Almost our entire supply of banabas, available year-round is
imported from central and south america. Bananas are sensitive to cool
temperature and will be induced in temperatures below 550f for this
reason, they should never be kept in the refrigerator. The ideal
temperature for ripening bananas is between 60 and 700f. higher
temperature cause them to repen too rapidly.
However, Bananas which are firm, bright in appearance,
and free from repeness is indicated by skin colour. Best eating quality
has been reached when the solid yellow colour is specked with brown.
At this stage, the flesh is mellow and the flavour is
fully developed. Bananas with green stips or with practically no yellow
colour have not developed their full flavour potential.
AIM AND OBJECTIVES
1. it shows the amount of bacteria present in the decay of banana
2. it also shows the amount of yeast and mold present in the decay of banana
3. it provides a basic understanding of the physical, chemical
and microbiological principles underlying the psreervation of foods and
also provide as a basic understanding of the study of food microbiology
from farm to consumer.
4. It provide students with an understanding of the physical and
chemical characteristics which influence the formation, stability and
texture of food systems
1.3 SIGNIFICANCE OF STUDY
This study is done to find out how similar or different
microorganisms associated with the spoilage of bananas are: it brings to
fore a good number of microorganisms associated with that or bring
about the spoilage of banana (musa acuminata). The significance of this
study can never and will never be over emphasized. This is because
banana is a fruit of choice and spoils easily. As a result of this, a
knowledge of the microorganisms that are involved in its (banana)
spoilage is essential.
Also, this study gives an insight into the conditi ons as
well as factors that result in the spoilage of this attractive fruit,
not to mention the nature or group of microorganisms that are associated
with such a fruit. The significance of this study is seen in the light
of having a good understanding and showing the comparism of the
spoilage microorganisms of banana.
1.4 STATEMENT OF PROBLEMS
A study of this nature must have problems which result in it. This
problem will result from how these microorganisms are being associated
with the spoilage of banana a fruit and cause decay to these banana and
make it undesirable for human consumption. This microorganisms
associated with the spoilage of banana includes yeast and
mold, {uedomonas species, micrococcus species, bacterial and fungal
species. Looking at many banana sold in the market today, most of them
are infected with these microorganisms or other microorganisms like the
soft rot, crown rot bacteria and soft rots which infect and make these
fruit unattractive for human consumption and may cause problems to
human being as well as animal.
1.6 HYPOTHESIS
Ho = Microorganisms are associated with the spoilage of banana
HI = Microorganisms are not associated with the spoilage of banana.