Isolation and Identification of Fungi Associated with Spoiled Tomatoes

Isolation and Identification of Fungi Associated with Spoiled Tomatoes

TABLE OF CONTENTS

Abstract

Table of Contents

CHAPTER ONE: INTRODUCTION

Background to the study

Statement of the Problem

Objectives of the study

Significance of the study

Research Questions

Hypotheses

Scope of the Study

Limitation of the Study

Justification

Definition of Terms

CHAPTER TWO: REVIEW OF RELATED LITERATURE

Brief history of Tomatoes Cultivation

Tomato production and postharvest spoilage in Nigeria

Over-view of disease symptoms due to fungi in tomato

Physiological disorders of Tomato

Control of postharvest diseases and losses of Tomatoes

Summary of related Literature

CHAPTER THREE: RESEARCH METHODS

Samples Collection

Materials Sterilization

Samples Processing

Isolation of Fungi

Characterization and Identification of the Isolates

Slide Culture Technique

Microscopic Examination

Gram Stain

Chlamydospore Formation Test

Germ Tube Test

Sugar Assimilation Test

Motility Test

Pathogenicity Test of the Isolates

Organoleptic Test

Taxonomic of Tomatoes

CHAPTER FOUR: RESULT AND DISCUSSION OF FINDINGS

Result

Discussion

CHAPTER FIVE: SUMMARY, CONCLUSION AND RECOMMENDATIONS

Summary

Conclusion

Recommendations

References

ABSTRACT

The study examined Isolation and Identification of Fungi Associated with Spoiled Tomatoes. It examined the various fugal pathogens associated with tomatoes spoilage as well as their preliminary taxonomic grouping up to genus level. 30 samples of the spoiled tomatoes were collected. Morphological studies reveal the fungi members which include members of the genus aspergillus, cladosporium, fusarium. Species of fusarium were seen to be the most occurring in all samples.

Statistical analysis also concurred to the fact that fungi are responsible for spoilage of tomatoes purchased. Therefore, it implies that fungi are greatly responsible for tomato spoilage. Proper handling, transportation and though washing with clean or chlorinated water will go a long way in reducing the risk of tomatoes spoilage by fungi.

CHAPTER ONE

INTRODUCTION

1.1          Background to the Study

Tomato (Solanum lycopersicum L.) belongs to the family solanaceae and it is an annual sub-tropical fruit vegetable crop. The crop originated from South America and was introduced to Europe in the 16th Century and later to East Africa by colonial settlers in early 1900 (Wamache, 2005). The Lycopersicon esculentum M. (tomato) is an important vegetable crop across the world, originated in West South America (Kimura and Sinha, 2008).

Without a doubt, ripe tomato fruits have high nutritive values, being a good source of vitamin A, B, C and minerals (Elsayed and Edrees, 2014). Because of the importance of tomato as food, it has been bred to improve productivity, fruit quality, and resistance to biotic and a biotic stresses (Kimura and Sinha, 2008).

Tomato is a major vegetable crop that has achieved tremendous popularity over the last century. However, tomato plants can grow up to 10 feet tall, but most species are less than three feet tall on average (Yoltao 1985). In addition, tomato plants are perennial, have a weak stem that often sprawls over the ground and vines over other plants (Sravanthi and Gangadhar, 2015).

Indeed, fruit of tomato are diverse in size and shape, ranging from small and round to large and variable shapes (Brewer et al., 2006). Thus, the size of tomato varies depending on the plant species. Cherry tomato plants produce small, cherry-sized tomatoes (Yoltao, 1985).

The crop is grown either on open field or under greenhouse technology. Open field production account for 95 % while greenhouse technology accounts for 5 % of the total tomato production (Seminis, 2007). Nigeria is among the Africa’s leading producer of tomato and is ranked 6th in Africa with a total production of 397,007 tones (Usam, 2012).

Certainly, tomato crop does well in warm climate with an altitude range of 0 – 2100 m above sea level. It requires rainfall ranging between 760 mm to 1300 mm and deep fertile loam soil that is well drained, with high content of organic matter and a pH ranging between 5-7 (Rice et al., 1994). Fruits are used in salads or cooked as a vegetable, processed into tomato paste, sauce and puree.

However, the nutritional value of tomato makes it a widely accepted vegetable by consumers. Fruits are rich in calcium, phosphorus, magnesium, copper, niacin, iron, folate, Vitamin A, B6, Vitamin E, Vitamin B2, Vitamin C, iron and carbohydrates (Wamache, 2005). Furthermore, the fruit has medicinal value as a gentle stimulant for kidneys, and washing off toxins that contaminate the body systems. Therefore, it improves the status of dietary anti-oxidants (lycopene, ascorbic acid and phenols) in diet (George et al., 2004).

Spoilage refers to any change in the condition of food in which the food becomes less palatable, or even toxic, these changes may be accompanied by alteration in taste, smell, appearance or texture. Colonization of fungi is a critical phase in the microbial spoilage of tomatoes.

The colonization process involves the ability of the microorganism (fungi) to establish itself without the produce (host). The contamination of tomatoes by fungi could also be as a result of poor handling practices in food supply chain, storage conditions, distribution, marketing practices and transportation.

Moreover, fungi affecting Tomatoes (Lycopersicum esculentum) includes Fusarium oxyspanium, Fusarium stolonifer, Aspergillus niger and Rhizopus stolonifer. Result on the percentage incidence and rot shows that Rhizopus stolonifer caused the greatest rot on tomato fruit. (Chuku, Ogbonna, Onue, 2012).

Undeniably, fruits and vegetables carry epiphytic micro flora. Fungi contamination of many agricultural products, including tomatoes starts in the fields (Aran et al., 1987).

Both the biological and physical damages during the harvest and transportation phases, coupled with large amount of water and soft endocarp makes tomatoes more susceptible to spoilage by fungi (Asan and Ekmeki, 2002: Onuoral and Orji, 2015). In addition, few studies on fungi associated with tomato spoilage are available in Nigeria (Wogu and Ofuase, 2014; Wokoma, 2008; Eni et al 2010: Bashir et al., 2016). Therefore, the present study isolates and characterizes fungi species associated with spoiled tomatoes in Nigeria.

Isolation and Identification of Fungi Associated with Spoiled Tomatoes

1.2          Statement of the Problem 

Unquestionably, tomatoes are an attractive cash crop for small scale farmers and provide potential source of employment to many Nigerians. Despite the human need of tomato, damage as a result of spoilage caused by micro-organisms has been of serious concern. In fact microbial decay is one of the main factors that determine losses and compromises the quality of the produce.

Both the biological and physical damages during the harvest and transportation phases, coupled with large amount of water and soft endocarp makes tomatoes more susceptible to spoilage by fungi.

In order to provide literature on this area, few studies on fungi associated with tomato spoilage are available in Nigeria. This then motivated the researcher to investigate into isolation and characterization of fungi associated with spoiled tomatoes.

1.3          Objectives of the study

This study aimed to examine the Isolation and Identification of Fungi Associated with Spoiled Tomatoes. Specifically, the study intends to:

(i)            isolates fungi species associated with spoiled tomatoes in Afaha Nsit; and

(ii)           characterizes fungi species associated with spoiled tomatoes in Afaha Nsit.

(iii)          To isolate the fungi organisms from spoilt tomatoes in Afaha Nsit.

(iv)         To characterize and identify fungi in spoilt tomatoes.

(v)          To determine the prevalence and pathogenicity of fungal organisms.

(vi)         To create public health awareness about the preponderance of fungal organisms.

1.4          Significance of the study

This study provides important information on the current status on isolation and characterization of fungi species associated with spoiled tomatoes in Nigeria and their management using crude plant extracts.

The outputs of this study will be important in reducing tomato post-harvest losses by improving the efficiency of post-harvest handling due to better post-harvest management strategies.

1.5          Research Questions

(i)            What are the fungi species associated with spoiled tomatoes in Afaha Nsit?

(iii)          What are fungi species associated with spoiled tomatoes in Afaha Nsit?

1.6          Hypotheses

Ho: fungi are not responsible in the spoilage of tomatoes.

H1: Fungi are responsible in the spoilage of tomatoes.

1.7     Scope of the Study

This present study places emphasis on isolation and characterization of fungi species associated with spoiled tomatoes in Nigeria.

Isolation and Characterization of Fungi Associated with Spoiled Tomatoes

1.8          Limitation of the Study

Despite that this research work was to highlight the microorganism association with spoilage of tomato, it was free with a lot of hindrances which include:

(i)            Time Constant: The research was constrained by the time limit, it posed a treat to the successful coverage intended in the course of this study. We also have a problem of managing time because we needed time to attend lectures which we have the time to do our practical.

(ii)           Cost Factor: The presence of economic hardship in our country posed to a great extent a problem in proving the whole material, information (and transportation) needed other statistical data procured was also limited by cost factor.

(iii)          Unavailability of research material.

1.9      Definition of Terms

Isolation: Is the process or fact of isolating or being isolated and may refer to sociology and psychology

Identification: Is the representation of persons (or other beings works of art.

Fungi: Fungi are any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds as well as the more familiar mushrooms.

Tomatoes: Tomato scientifically known as Solanum lycopersicum, is a herbaceous plant usually sprawling on ground in the solanacea family and they are close family to tobacco, chili peppers and egg plant.

CHAPTER TWO

REVIEW OF RELATED LITERATURE

This section deals with the review of literature related to this study.

2.1          Brief history of Tomatoes Cultivation

Tomato (Lycopersicon esculentum Mill.) is one of the most popular and widely grown plants in the world as well as in Africa (Osemwegie, et al., 2010). It is the second most important vegetable worldwide, in terms of the amount of vitamins and minerals it contributes to the diet (Enrique & Eduardo, 2006).

Genetic evidence shows that the progenitors of tomatoes were herbaceous green plants with small green fruit and a center of diversity in the high lands of Peru (Smith 1994).

The Spanish explorer, Cortes may have been the first to transfer the small yellow tomato fruits into Europe after he had captured the Aztec city of Tenochtitlan, now Mexico City in 1521; although Christopher Columbus, a Genoese working for the Spanish monarchy may have taken them back as early as 1493.

The earliest discussion of tomato in European literature appeared in an herbal written in 1541 by Pietro Andrea Mathiolian Halian, an Italian physician and botanist, who named it pomod’oro, or ‘gold apple’ (Smith 1994). One of the earliest cultivators was John Gerard, an Herbal-Surgeon. Smith (1994) reiterates that Gerard’s Herbal, published in 1597, and largely plagiarized from continental sources, is indeed one of the earliest discussions of tomato in England.

Similarly, Tindall (1988) remarked that the Portuguese trader and freed slaves from West Indies introduced this plant into West Africa Countries.

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