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 epiphytic flora of plants.
1.1 INTRODUCTION 1
1.2 AIMS 9
1.3 SIGNIFICANCE OF STUDY 9
1.4 STATEMENT OF PROBLEM 10
1.5 LIMITATION 11
2.0 LITERATURE REVIEW 12
2.1 MICROBIOLOGY OF BANANA 12
2.2 MOULDS 16
2.3 YEAST 18
2.4 BACTERIA 19
2.5 BACTERIAL SPOILAGE OF BANANA 20
2.6 FUNGAL SPOILAGE OF BANANA 21
2.7 OTHER FUNGAL SPOILAGE OF BANANA 23
2.8 CONTROL OF BACTERIAL AND FUNGAL DISEASES 24
3.0 MATERIALS AND METHOD 27
AGAR 29
BANANA FRUIT 30
IDENTIFICATION 31
4.0 RESULTS 35
4.1 BACTERIAL EXAMINATION 36
4.2 FUNGI EXAMINATION 40
5.0 DISCUSSION 43
5.1 CONCLUSION 45
5.2 RECOMMENDATION 46
REFERENCES 48
TABLE ONE: CHARACTERISTICS OF BACTERIA ISOLATES
TABLE TWO: BIOCHEMICAL ISOLATE FOR BACTERIA
TABLE THREE: COLONIAL CHARACTERISTICS OF FUNGI ISOLATES
Banana may be defined as a personal seed plant that produces an edible fruits, usually seedless, belonging to the species Musa acuminata, or are hybrids Musa acuminata, M. balbisnna. They are perennial herbs with long leaves, the bases of these leaves (petioles) remain tightly fused and form the trunk (Pseudostem) of a plant 2-9m 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 mono carpic, flowering and setting fruit once before sit dies. It has inflorescence protective flag leaf. The flower stalk of most banana varieties is positively geotropic and bends from the vertical until its tip points towards vertical. Flower stalks are from 30 – 90 cm along, tapered and covered in a sheath of over- lapping bracks the flower are parthenogenic (self-fertile). And occur in group of 12-20 beneath the bracks.
At first, individual fruits 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 rhizome. As old plant dies, new sucker are formed the rhizome expands and is called a mat. Banana are propagated by suckers, pieces of the Rhizome and by tissue cultivation (Ploetz, 1994)
Bananas contain about 74% water 23% carbohydrate, 1% protein and 0.5 %, Vit., 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 pure for in a variety of products including ice cream, yoghurt, cake, bread, nectar, and baby food. Ripe bananas can be dried and eaten, or sliced canned with syrup, and used in bakery products, fruits salads etc. Green (unripped) 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 to feed cattle and hogs. Bananas are a good energy source but need to be supplemented with protein.
But, not all micro-organisms associated with fruits are harmless”. This includes the lactic acid bacteria, coryne forms, pseudomonas, xanthomonas micrococci, any 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 microorganisms per gram. The presence of any of these microorganisms is a concern for causing product spoilage.
Food spoilage is a major problem 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 the environment where the food is being stored or what are described as extrinsic factors. Food composition is critical intrinsic factor that influences microbial growth. 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 mould. 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 fruit has outer skin (peels) that protect them from spoilage.
Often, spoilage microorganisms 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 can.
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 moulds. 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. 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 plant material; disposal of infected fruits and plant part.
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, to plant resistant cultivans. Such as the ‘pelipita’ plantain.
Thus fungus is often responsible for the rotting of bananas in storage. Immersing the green fruits in hot water. 3250k (55oc) for 2 minutes before ripening greatly, reduces spoilage.
Bananas are sensitive to cool temperature and will be induced in temperatures below 2860k for this reason, they should never be kept in the refrigerator. The ideal temperature for ripening bananas is between 288 and 2940k higher temperature cause them to ripen too rapidly.
Banana which are fair and bright in colour with yellow flesh and fully developed flavour indicates best for consumption. Bananas with green stips or with practically no yellow colour have not developed their full flavour potential.
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