1.1 Introduction
Orange is from the citrus family, the fruit size varies with cultivar and crop load, but most often measures between 2.5-4 inches in diameter. The shape of the fruit is spherical to oblong, with a peel thickness between that of grape fruit and tangerine and is either smooth or roughly pebbly. The presence and amount of seed, depends also on the cultivar (Nwobi et al., 2006).
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, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Citrus sinensis (L.), family Rutaceae, is one of the major commercial fruit crops that are widely consumed both as fresh fruit or juice due to its high vitamin C content and antioxidant potential (Gorinstein et’al., 2001). Isolation and identification of the pathogens are desirable in order to strategize the control measures with a view to reducing losses due to spoilage or infections (Singleton et al., 1992). Occasionally, a disease is caused by new, previously unknown pathogens that must be isolated and studied. Spoilage microorganisms can be introduced into the crop on the seed itself, during crop growth in the field, during harvesting and postharvest handling, or during storage and distribution (Barth et al., 2009). Most citrus fruits are, in association with a variety of bacteria, and fungi, but due to a particular environmental condition, only a small proportion of the kind of microorganism(s) present will be able to grow rapidly and cause its deterioration (Alfred and Patrick, 1985).
Postharvest losses and decay of Citrus fruits can be traced to infections that occur either between flowering and fruit maturity or during harvesting and subsequent handling and storage activities. Pre-harvest infections are mainly caused by fungal pathogens such as Phytophthora spp, Colletotrichum glocosporiodes (Browning et al., 1995: El Ghaouth et al., 2002). Apart from mycotoxin contamination of orange fruits, the presence of fungi eventually leads to disease development in the field when the infected seeds in the fruits are planted. Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Mycoflora Responsible for Spoilage of Sweet Orange (Citrus Sinensis).
1.3 Statement of Problem
Microorganisms are associated, in a variety of ways with all the food we eat. They may influence the quality, availability and quantity of our food such as fruits and vegetables which normally contain some microorganisms and maybe contaminated with additional organisms during handling (Lund, 1971). Food can serve as the medium for the growth of microorganisms and as a result transmit diseases. Other microorganisms, if allowed to grow in certain food products, produce toxic substances that result in food poisoning when ingested (Pelczar, 1993). Different disease problems arise when crops are harvested, because seed, fruit or other storage organs are essentially dormant structures and their cells are physiologically unlike those of growing plant (Daveport, 1978).
1.4 Aim and Objectives of Study
The aim of the study is to scrutinize the Mycoflora Responsible for Spoilage of Sweet Orange (Citrus Sinensis). In achieving this aim, the following specific objectives were laid out as follows:
- To isolate and identify fungi associated with post- harvest deterioration of sweet orange fruits
- To isolate and identify the fungal organisms responsible for the post‒harvest spoilage of sweet orange fruits.
1.5 Significance of Study
Sweet Orange (Citrus Sinensis) play a vital role in human nutrition by supplying the necessary growth factors such as vitamins and essential minerals in human daily diet and that can help keep a good and normal health. They are widely distributed in nature and can play an important role in health through the prevention of heart disease and cancer. This study will be of immense benefit to 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.
1.6 Scope of Study
The study focuses on Mycoflora Responsible for Spoilage of Sweet Orange (Citrus Sinensis) in Sokoto metropolis.
1.7 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).
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