Identification Of Microorganism Associated With The Spoilage Of Watermelon

CHAPTER ONE

1.0                                                        INTRODUCTION
1.0                                           BACKGROUND OF THE STUDY

Watermelon is one of the most sought-after fruits in tropical Africa because of its delicious taste and nutritional value.Watermelon (Citrulluslanatus) is a member of the cucurbit family commonly referred to as Cucurbitaceae (Huh et al., 2018); a warm-season crop related to cantaloupe, squash, cucumber and pumpkin (Georage et al., 2010). It is an important horticultural crop, mostly known for its sweet and juicy fruit, grown commercially in areas with long frost-free warm climates all over the world (Jeffreyet al., 2011). Baba et al., (2014) reported that watermelon global consumption is greater than that of any other cucurbit. It is highly relished as a fresh fruit in different parts of the world because of its thirstquenching attribute in addition to many other identified nutritional values and advantages (Ajewole, 2015). The consumption of the commodity in the recent times has witnessed remarkable development as it cuts across all socioeconomic classes.

Nigeria is one of the leading producers of watermelon in Africa, and the largest production of the crop comes from the Northern part of country, where the suitable agro ecology is found. However, a reasonable quantity of the crop could still be grown in other agro-ecologies with intensive management and is still economically feasible (Bosede et al., 2012).

Outbreak of illness caused by consumption of fruits had been reported (Abdul-Raouf et al., 2013). Spoilage of watermelon is associated with microorganisms. The increase in consumption of contaminated watermelon has been linked with a parallel increase in food borne illness. Fruit produce is known to carry a natural non- pathogenic micro flora, and have an epidermal layer of cells which provides a barrier for penetration of microorganisms.

Therefore, this study was undertaken to identify microorganism associated with spoilt watermelon.

1.2                                   PROBLEM STATEMENT

The consumption of exotic vegetable including watermelon has been on the increase in Nigeria according to Okorie (2012). Watermelon being a perishable agricultural produces and cannot be stored over a long period of time; it got spoil after short period of time. Spoilage of watermelon is associated with naturally occurring pathogenic microorganisms. Such pathogens cannot be detected organoleptically (seen, smelled or tasted), but can cause disease of varying severity, including death specially if the way they are conserved during exposition for sales provides conditions for those microorganisms to grow and reach considerable levels of contamination. This study was carried out to identify these micro-organisms especially those that are pathogenic to humans so as to reduce the risk of contamination and infection arising from spoilt fruits.

1.3                                                     AIM OF THE STUDY

The aim of this study is toidentify microorganism associated with the spoilage of watermelon.

1.4                                              OBJECTIVES OF THE STUDY

The objectives of the study are:

1. To identify microorganism responsible for the spoilage of watermelon.
2. To study the impact of eating spoil watermelon

• The effect of microorganism on human health

1.5                                           JUSTIFICATION OF THE STUDY

Microorganism associated with spoilage of watermelon such as Staphylococcusaureus, Salmonella, Campylobacter, Escherichia coli, molds, and yeasts can also contaminate the water melon thereby making dangerous for human consumption – causing food-borne diseases in humans. This study is important in that it will serve as a means of educating consumers of water melon on how to avoid eating contaminated fruit (water melon)

1.6      MATERIALS

Materials used are:

1. Sterile knife and wearing sterile disposable hand gloves (for taking watermelon sample).
2. distilled water

• glass beaker

1. Nutrient agar
2. Eosin methylene blue agar (EMB)
3. SalmonelleShigella agar (SSA)

1.7                                                              METHODS

One gram from each of the water melon shall be obtained (using a sterile knife and wearing sterile disposable hand gloves) and transferred into 9 ml of distilled water in a glass beaker, thereafter shakethoroughly. Serial dilution of the solution was done by transferring 1ml into 9 ml of distilled water. From theappropriate dilution, 0.1ml was plated onto different media using the spread plate technique. Nutrient agar, Eosin methylene blue agar (EMB), SalmonelleShigella agar (SSA) were used for bacterial enumeration and identification while Sabouraud dextrose agar (SDA) was used for fungi. Each inoculated sample was in duplicates and the plates were incubated for 24 to 48 hours at 37 C for bacterial growth, and 72 hours at 25^oC for fungal growth on SDA plate. Thereafter, the plates were examined for growth and the colonies counted and recorded as cfu/g. The morphological and microscopic features of the colonies were also noted. Gram stain reaction, motility test and biochemical (catalase, coagulase, oxidase, indole production, sugar fermentation) were performed for identification of bacteria (Cheesbrough, 2012).

1.7      Expected result

The result shall identify different microorganism that are associated with spoilage of water melon, including those of public health  importance which could be responsible for food borne infection.