1.1 Introduction
Avocado pear is a member of the family Lauraceae, which are mainly shrubs and trees that yield resinous aromatic gum from their cut bark. It is among the well-known indigenous fruit trees in the tropical and subtropical rain forest zone of the Southern regions of West Africa. Avocado fruit used in commerce are picked hard and green and kept in coolers at 3.30 to 5.60C, until they reach their final destination. Once picked, avocados ripen in a few days at room temperature. The fruit has a very short shelf-life. It can averagely be stored 3-6 days before spoilage. The poor shelf life of the fruit has led to its high perishability, huge losses and market glut during harvest as noticed by large heaps of unsold rotten fruits in the refuse dumps of village and urban markets.
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Avocado pear is a member of the family Lauraceae, which are mainly shrubs and trees that yield resinous aromatic gum from their cut bark. It is among the well-known indigenous fruit trees in the tropical and subtropical rain forest zone of the Southern regions of West Africa (extending eastward from Sierra Leone to Nigeria and Western regions of Central Africa, which includes Cameroun, Equatorial Guinea, Gabon, Democratic Republic of Congo, Congo Brazzaville and Angola). The fruit is a pome, characterized by a central core surrounded by edible fleshy layers (Barry, 2001).
The Avocado fruit has a pulpy mesocarp of 3 to 9 mm2 thickness, 7cm-20cm long, weighs 100g – 1000g and has a large central seed, 5cm – 6.4cm long. The skin texture is finely pebbled and dull green when ripe. The high spoilage rate of Avocado fruit coupled with its high nutritional contents pre-supposes that an array of microorganisms may be involved in its spoilage of Avocado fruits. Spoilage is always a concern to anyone who purchases fresh fruits. An increase in local acceptability of fresh fruits indicates that a proper understanding of factors of spoilage or prolonging freshness of fruits is of increasing importance to consumers.
The composition of the fruit influences the likely type of spoilage. Thus bacteria soft rot is widespread for the most part among the fruits is limited to those that are not highly acid. Because most fruits are somewhat acid are fairly dry at the surface, and are deficient in B vitamins, mold are the most common causes of spoilage. The compositions too, must determine the particular kind of molds most likely to grow, thus avocado support a large, variety of fungal spoilage organisms and other kinds comparatively few.
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Microbial Examination of Spoilt Avocado Fruit.
1.3 Statement of Problems
Investigation revealed that micro-organisms are known to destroy fruits, thereby reducing the quantity for consumption and the profits desirable from fruits such as avocado. Many spot are noticed on pears which do change the taste when consumed.
Bacteria and fungi are harmful and useful living organisms. The spoilage of most fruits is always associated with bacteria and fungi, many diseases of plants are associated with bacteria and fungi (Micro-organisms).
The adverse effect of bacteria in plants and fruits has resulted in shortage of avocado fruits for consumption. Revenue is lost by farmers and industries that uses avocado fruits as a raw materials for fruit juice due to the spoilage caused by micro-organisms.
1.4 Aim and Objectives of Study
The aim of the study is to carry out a Microbial Examination of Spoilt Avocado Fruit. In achieving this aim, the following specific objectives were laid out as follows:
- To isolate and identify how micro-organism destroy avocado so as to guide producer and farmers on how to manage the fruits.
- To compare the extent of spoilage in the area of colelction (tree) with that of market.
- To isolate and identify it those micro-organisms are responsible for the spoilage.
1.5 Research Hypothesis
In order to pursue the objective of this study, the following generalized statements have been designed to guide and aids in obtaining the result for the experiment to be conducted. For this work, the null hypothesis will be represented with H0 while the alternative hypothesis will be represented with hypothesis H1.
Hypothesis One
- H0: Microbial organisms do not cause spoilage of avocado at either in the field or during exposure for sale.
- H1: Microbial organisms do cause spoilage of avocado at either in the field or during exposure for sale.
Hypothesis Two
- H0: Microorganisms (Fungi and Bacteria) are not responsible for avocado spoilage.
- H1: Microorganisms (Fungi and Bacteria) are responsible for avocado spoilage.
1.7 Significance of Study
This study will be useful to farmers, fruit juice industries and consumers of avocado fruits. The outcome of this research will guide users of avocado fruit on the best method of preserving to avoid spoilage, the research work also will add to the literature and information existing about avocado for student and companies that uses avocado as raw materials for the production of fruit juice.
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.8 Scope of Study
The scope of the research is focused on Microbial Examination of Spoilt Avocado Fruit.
1.9 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
