Microbial Examination of Spoilt Avocado Fruit
Chapter One
AIM AND OBJECTIVES OF THE STUDY
Microbial examination of spoilt avocado fruits
To isolate and identify how micro-organism destroy avocado so as to guide producer and farmers on how to manage the fruits
To isolate and identify it those micro-organisms are responsible for the spoilage
To compare the extent of spoilage in the area of colelction (tree) with that of market
CHAPTER TWO
LITERATURE REVIEW
THE ORIGIN OF AVOCADO FRUITS
The avocado pear, otherwise known as persea Americana miller originated from south America where it has been an important part of diet for thousands of years. The fruit of various species of persea, a genus nature to Mexico, Guatemala, and other central American countries, has been used for food by the inhabitants of those countries for countries. Selections from those wild trees, of California, Florida and Texes. World production is nearly 2 million tonnes, of which a small proportion is grown for export, mainly in California (Lee and young 1984)
Cultivars vary greatly in size, shape and colour of their fruits, fuerte (a guntermalen type) is thick, woody and knobbed, turning purplish black as the fruit ripens. Common to all avocado is a rich, smooth, oily pulp which is eaten as a nutritious savoury. The centre is a large stone, the seed . In warm and humid areas such as south east Florida and all world low lands near the Equator, only the West Indian race is well adapted but West Indian Xguatemalan hybrides are doing well and becoming increasingly important in extending the harvest season
USES OF AVOCADO FRUITS
Avocado fruits persea Americanna, is a delicious fruits the fruits is very useful in fruit juice production. Many manufacturing companies see Avocado fruit as very important raw material for the production of fruit juice. The sale of avocado fruits yield revenue to local fanuas.
It is consumed as a good source of mineral or vitamin.
PRESERVATION OF AVOCADO FRUIT
Avocado fruit is highly nutrition, there a re many ways it can be preserved and retained it potential nutrients.
Drying method: Avocado fruits can be diced into bits and dried in an open air oven or in air depends on the concentration of the heat. This dried avocado fruit may be grind into fine powered and use as a food supplement.
Frozen method: This is by use of refrigerator preserved avocado fruit, it is use when need
Canned method: this is another method of preservation most applicable to fruit juice industries. dried avocado
WAYS AVOCADO FRUIT CAN BE PRONE TO CONTAMINANTS
As soon as avocado fruits are gathered into boxes, lugs, baskets or trucks during harvesting, they are subjected to contamination with spoilage organisms from each other and from the container unless these have been adequately sanitized. During transportation into market or the processing plants. Mechanical damage may increase susceptibility to decay and growth of micro-organisms may take place. Pre-cooling of the product and growth of micro-organisms. Washing the avocado fruit may involve a preliminary soaking, may be by agitation in water or preferably, by a spray treatment soaking and washing by agitation tend to distribute spoilage organisms from damaged to whole fruits recalculation or reused water is likely to add organisms and the washing process may moisten surface enough to permit growth of organisms during a holding period. Avocado washed with detergent or gerundial solution have reduce number of micro-organisms on them (shepherd, 1990).
CHAPTER THREE
MATERILAS AND METHODS
SAMPLE COLLECTION
Ripe and mildly ripe avocado with blemish or lesion on the body (slightly infected avocado) were bought from Ogbete main market and New Market in Enugu. Also, ripe avocado fruits without blemish was collected and used as control measured. The area with blemish was group ‘A’ while the others without blemish was group ‘B’ the control group, which was deprived of certain factors that was not accessible to the study populations. The control group was allowed to enjoyed some privileged not accessible to the study group. 10 avocado for control group total number of avocado used was 60, 30 from each market.
STERILIZATION OF MEDIA AND MATERIAL USED
Sterilization of the glass materials used example petridishes, pipette, flask, test tubes etc. was done by autoclaving at 1210c for 15 minutes. The heat labile materials were autoclaved at 1210c for 8 minutes.
The culture media used include, nutrient agar (NA) and sabourand dextros agar (SDA). These were obtained in the commercially prepared powered (hydrated) forms and prepared according to the manufacturers instructions. The specified quality was dissolved in specified volume of distilled water and sterilized by autoclaving at 1210c 15 minutes in well stoppered conical flask. Each flask and its contents were allowed to cool for about 450c – 500c before dispensing into pre sterilized petri dishes under steriled conditions. The media was steriled into bijoux and left in slanting position to get 250 mg of chloramphaenicol was added to SDA and mixed properly just before fouring into plates aor bijoux bottles in order to exclude the growth of bacteira that have the capacity of rowing in the SDA.
CHAPTER FOUR
RESULTS AND DISCUSSION
RESULTS
In all, a total of 60 avocado fruits were obtained from the two sources viz; Ogbete main market and New market respectively in Enugu state. Each avocado fruit was examined for Fungi and bacteria associated with its spoilage by both physical examination and culturing on both nutrient agar and SDA containing chloramphenicol.
In this work, six bacterial and six fungal species were isolated. The bacterial isolates were Erwinia sp, Staphylococcus sp, Psudomonas sp, sp, with Erwinia species occurring 25 time (highest occurrence) and Chromobacter having the least occurrence of 3 times. The fungal species observed Aspergillus sp, Pericilium sp fusarium sp, Rhodotorulla sp, Rhizopus sp and carovularia sp.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
CONCLUSION
Considering the data obtained from this work, bacteria and fungi spoilage of avocado will continue to increase. If not controlled. The percentage (frequencies) of occurrence of the various isolates showed that in the case of fungi isolates the Aspergillus sp, Penicillium sp. Rhizopus sp with Fusarium are the worst agents of spoilage of avocado in the study area, on the other hand in the case of bacteria Erwinia sp, chromobacter sp have been found to be pathogenia for man and animals, so can cause health problems to man. It therefore follows that any method used to control or reduce these micro-organism will drastically reduce the spoilage of fruits. When this fungi and bacteria spoilage is reduced, more of the fruits will be available for human consumption
RECOMMENDATION:
On health ground, it is advisable not to consume spoilt avocado fruits in order to avoid very fatal infections in human beings, example Chromobacterium sp can causes pyogenic infection in from infected avocado.
REFERENCES
- Bezurdenhout, J.J. (1972) ‘Analysis of transit temperature fruitcondition of south Africa export avocado’ Year book of south Africa Avocado Browners Association pp:39-40
- Coffey, M.D. (1992) Phytopthora root rot of avocado diseases of fruit crops pp:423 – 444
- Debek A.J. (1993) Out break and new records of Ethiopia avocado leaf necrosis and lethal conditions of acadia in Ethiopia. FAO Plant protection Bulletin Pp: 31-33
- Duvenhage: J.A; (1993) ‘The influence of wet picking on post harvest diseases and disorders of Avocado fruit’’Year book of south Africa Avocado Grower Association pp: 77-79
- Eloit E.S (1957) ‘Aspects of late hung “Hass” avocado fruit in the Natalmidlans and their concomitant bacteria: Journal of Agricultural science pp:39-45
- EL – Hamalaw. Z.A. and J.A Menge. (1994) Avocado trunk canker disease PP:700-704
- Korsten L: Villners E.E.Rowell A. and Kotze J.M (1993) ‘Post harvest biological control of avocado fruit diseases’ Year book o
