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.

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