Isolation of Microorganisms Associated With Deterioration of Bananas Fruits
Chapter One
Aim of the study
To isolate microorganisms associated with the deterioration of banana fruits and to assess common ways used to improve the shelf life of the fruit sold in Makurdi Benue state.
The specific objective of the study
- To isolate and identify microorganisms associated with spoilage of fresh Banana fruits in Makurdi.
- To isolate and identify microorganisms associated with spoilt banana fruits sold in Makurdi.
- The distribution of spoilage microorganisms among markets in Makurdi.
- To determine the physio-chemical parameters of banana pulp.
CHAPTER TWO
Literature review
Spoilage of banana fruit is mostly caused by organism such as fungi muld and bacterial. Spoilage type can be identify mostly by physical examination of the fruit. Fungi mucor and muld mostly cause whitish small growth and stain on the peel of banana, but bacterial causes soft rot of the fruit. Microorganism associated with the deterioration of banana fruit where isolated. Fungi isolated were Rhyzotonia solani, Aspergillusniger, bacterial isolated were Streptococcus pyogenes, Proteus vulgaris, Alcaigenes faecalis and Streptococcus faecalis, (Oyewole, 2012).
Botanical description.
The banana fruit is an edible fruit, botanically a berry, produced by several kinds of large herbaceous flowering plants in the genus musa. The fruit is variable in size, color and firmness, but is usually elongated and curved, with soft flesh rich in starch covered with a rind which may be green, yellow, red, or brown when ripe. The fruits grow in cluster hanging from the top of the plant. Almost all modern edible parthenocarpic (seedless) bananas come from two wild species. Musa acuminata and Musa balbisiana, (Nelson, 2006).
Cultivation
Bananas need warm subtropical climate, adequate moisture and protection from wind, most varieties of bananas grow best with 12 hours of bright light and high humidity of 50% or higher. The ideal temperature is around 260-300c (78-86F) (Wartentin et al., 2004).
NOTE: Three key tips for packing:
- cool the fruit in the packing shed with sprays or water dips.
- Cool the packing shed with forced air (not lower than 140c)
- Refrigerate the fruit while it is being transported to market
The ripening of banana is caused by some biochemical process of transformation of starch to sucrose during ripening of bananas involves several enzymes and more than one pathway. The disappearances of starch reserve during banana ripening is very fast. The average starch content drops from 25% in the prelimaterial phase to less than 1% during the climateric period. Ripening process of banana is different from spoilage or deterioration of banana by microorganisms, ripening process is a natural biochemical process, during the process, there is a rapid conversion of the starch in the banana into sucrose
Bacterial diseases of Banana
Rhizome rot
Causative Agent: Erwinia coratovora and Erwinia chrysanthemi
Symptoms
Psedostem breakes from rhizome; rhizome will not germinate,internal tissue yellow/brown and watery.
Comments: Bacteria lives in the soil and enter plant through wounds, diseased by wet humid conditions
Management: select only high quality, disease free rhizomes for propagation, disinfect all tools used for propagation regularly, allow seed pieces to dry before planting, (Ploatz et al., 2002).
Moko disease
Causative Agent: Ralstonia solonacearum
Symptoms: Older leaves chlorotic, wilted and collapsing, spreads to entire canopy, collapse of psuedostem.
Comments: can be spread root to root by insects or humanactivities such as machete pruning
Management: banana plantains should regularly monitored for presence of disease, infected plants may heed to be destroyed along with any neighboring plants. Tools should be thoroughly disinfected, (Ploatz et al., 2002).
Fungal diseases of Banana:
Black sigotaka (Black leaf streak):
Causative Agent: Mycosphaerella fijiensis
Symptoms: Red/brown flecks on spots on underside or topside of leaves, spots with dark or yellow border and grey centre, death of leaf surface, bunch not developing
Comments: currently the most important disease of banana, promoted by high moisture and spores spread by wind
Management: Export plantations may require regular fungicide applications increase air circulation and reduce humidity, remove leaves with mature spots, (Ploatz et al., 2002).
CHAPTER THREE
Materials and Method
The Study Area
Makurdi Is the capital of Benue State which is one of the 36 states of the Federal Republic of Nigeria and it is referred to as the food basket of the Nation. It was created on February 3, 1976 with Makurdi as the capital city. The state has 23 Local Government Area (LGAs) with a population of 4,219,244. The state occupies a landmass 30,955 square kilometers. Benue State is located between latitudes 6o 30’N and 8o 10’N and between longitudes 7o 30’E and 9o 50’E. it is created in the middle belt of the Nigeria and derives its name from River Benue which is the second longest river in Nigeria. The state lies in the transition belt between tropical rain forest of southern Nigeria and open grassland savannah vegetation of northern Nigeria (Benue State Diary, 2007). Benue State experiences a typical tropical climate with distinct seasons, the rainy season and dry season. The rainy season last from April to October with annual rainfall in the range of 150-180mm. the dry season begins in November and ends in March while mean monthly temperatures fluctuate between 23 and 30oC in the year.
Benue State is endowed with abundant agricultural resources. About 80% of the population depends on agriculture for their sustenance and livelihood. The state has favourable climate conditions and fertile soil conductive for the rearing of animals and cultivation of virtually all crops grown in Nigeria. Most prominent among the animals reared are pigs, goats, poultry and cassava major crops cultivated include; yam, cassava, rice, soya bean, Sesame, maize, citrus, mangoes, vegetables and sugarcane. The state has high migrant population of nomads, Fulani pastoralists whose main occupation is raising cattle.
Sample Collection
One hundred (N=100) samples of fresh and spoilt banana were collected from banana vendors from five different markets in Makurdi metropolis over five weeks. Ten samples (5 fresh and 5 spoilt) were asetically collected from each market once a week in clean polythene bags separated and taken to the Advance Research Laboratory, Department of Biological Sciences UAM, for identification and analysis
Media Preparation
The media used for the experiment were nutrient agar and sabroud dextrox agar for isolation of bacteria and fungi respectively. The media where prepared using manufacturers instruction and sterilized using autoclave at 121oC for 15 minutes.
CHAPTER FOUR
RESULTS
Five different types of fungi and three bacteria isolates were obtained in this study. Fungi isolated from these sample examined include; Aspergillus niger, Rhizopus spp and penicillium. The yeast isolated was Candida spp, Mucor was also isolated, three strains of bacteria identified by their biochemical characteristics were Staphylococcus aureus and Streptococcus species isolated the fresh banana while Cocobacilli species was strickly isolated from the spoilt banana.
Yeast cells were the most isolated fundal isolates in spoilt Banana. While penicillium and Aspergillus niger had the least fungal isolate rate (Table 4).
Streptococcus pyogenes were the most isolated Bacteria species in fresh Banana, it occurrence was 16(32%) while Staphylococcus aureus shows percentage occurrence of 9(16%), (Table 5).
CHAPTER FIVE
Discussion, Conclusion and Recommendation
Discussion
This study shows that the fungi Aspergillus niger, Rhizopus spp, penicillum spp, Mucor and yeast strain identified as Candida species are important agents of spoilage of banana fruit.The bacteria identified in this study are Staphylococcus aureus, Streptococcus and Coccobacillii species. Pathogenicity test carried out suggest that the role of bacteria as banana rot causing organisms is minimal since result shows no much difference from the test control.
This disparity in the result seems to suggest that although a lot of banana spoilage organisms starts from the farm and candida spp could be post harvest contaminants acquired probably during transportation from the farm to the market.
It was not surprising to isolate S.aureus from some of the samples of tomato examined .It is a micro flora of nostrils skin and land of man .it might have come from the trader or the air .the result of this work shows that banana fruit the contaminants of banana fruit comes from the farm, the routes in which the banana pass through to the market and the handlers.
Conclusion
Banana production and storage is faced with a lot of challenges, especially in prolonging the shelf life.
This study shows that microorganism especially fungi, causes deterioration and spoilage of banana fruits and consumption of some of the infected bananas fruit causes disease in man as a result of toxics secreted by fungi, e.g Aflatoxin.
Some of these microorganisms are fungi while others are bacteria. Bacteria spoilage of banana fruit in less compare to the fungi spoilage of banana. Since banana has a Ph that is slightly acidic, it is most likely to be spoilt by fungi.
Some of the common contaminating microorganisms which were isolated from the banana fruit already spoilt could come from the farm while some of the microorganisms were acquired as post harvest contaminant probably in temporary storage and in transit which finally manifest their spoilage activities in the market.
The careless handling and storage of banana fruit which to bruise or cut on the banana peel causes spoilage of the fruit as a result of penetration and activities of microorganism. Storing the banana in a dirty environment or the use of dirty tables and rages used in covering tables increases the incidence of contamination.
Various spoilage condition and environmental situation also increases the rate of spoilage of the fruit e.g. The fruit should be stored at room temperature and in the refrigerator should be stored at a temperature of 140c .The handlers should prevent bruises and injuries on the banana fruit.
Recommendation
- Wound on the surface of banana fruit can serve as entry points for the rot inducing microorganism. It is advisable therefore to ensure acceptable handling procedures during harvest and transportation operation to reduce wounds caused by mechanical injuries(such as cuts, puncture etc made on the fruits) which may serve as portal entry for those microbial pathogen .
- Damaged banana can harbor pathogen so when a pathogenic microorganisms such as fungi and bacteria.
- Blanching of banana fruit before storage is also very important because it help neutralizes bacteria present on fruits, delaying spoilage.
- Manual harvester should be well trained in the proper way to harvest the crop to minimize damage and waste.
- The container used by harvesters to gather the fruit should be clean, have smooth inside surfaces and be free of rough edges which could damage the banana and present portal entry for microorganisms.
- During transportation to the market the fruit or boxes should be covered with soft cloths to prevent abrasion of the fruit.
- Sanitation must be effective at each of steps of handling and distribution.
REFERENCES
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- Agbabiaka TO, Sule IO (2010). Bacterial Assesment of selected Borehole water Samples in ilorin metropolis. International Journal of Applied Biology Research 2010: 2(2). 31-37.
- Armstrong, Wayne P (2013). “Identification Of Major Fruit Types” . Wayne’s Word: An On- Line Textbook of Natural History . Retrieved August 17, 2013.
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