Microbial Contamination Of Vended Fruit

In West Africa the seeds are made into pulp and added as thickener to soups. They are also fermented to produce a sweetener locally called ‘ogiri’ or they are roasted, pounded, wrapped in leaves and then boiled to produce another sweetener called ‘igbãlo’. The residue from oil extraction is made into balls that are fried to produce a local snack called ‘robo’ in Nigeria, or is used as cattle feed. The residue from oil extraction is made into balls that are fried to produce a local snack called ‘robo’ in Nigeria, or is used as cattle feed (Loiy Elssir et al., 2011).

Immuno-histochemical analysis showed watermelon that effectively protected pancreatic cells death, which suggest that watermelon has a beneficial effect on diabetes (Jiyun et al., 2011). Watermelon has also shown to have a significant gastroprotective effect in Indomethacin-induced gastric ulceration (Francis et al., 2013). Watermelon acts as a good antioxidant, anti-inflammatory and analgesic potential and may be used as a future food medicine (Gill et al., 2010). The results of the extraction of aqueous fruit pulp from Citrullus lanatus showed a significant laxative activity of watermelon (Swapnil et al., 2011).

2.3. CUCUMBER
2.3.1. Introduction
Table 2: Scientific Classification of Cucumber
Kingdom:     Plantae
Order:         Cucurbitales
Family:     Curcubitaceae
Genus:     Cucumis
Species:     sativus
(Source: Enujeke, 2013).

Cucumber (Cucumis sativus) is a widely cultivated plant in the gourd family, Cucurbitaceae. It is a creeping vine that bears cylindrical fruits that are used as culinary vegetables. The cucumber plant is a coarse, prostrate annual creeping vine that grows up trellises or any other supporting frames, wrapping around ribbing with thin, spiralling tendrils. The plant has large, prickly, hairy triangular leaves that form a canopy over the fruit, and yellow flowers which are mostly either male or female. The female flowers are recognized by the swollen ovary at the base, which will become the edible fruit. Botanically, the fruit is a false berry, elongated and round triangular in shape. Its size, shape, and colour vary according to the cultivar (Okonmah, 2011).

2.3.2. History
The cucumber most likely originated in India (south foot of the Himalayas), or possibly Burma, where the plant is extremely variable both vegetatively and in fruit characters (Doijode, 2001). It has been in cultivation for at least 3000 years. From India the plant spread quickly to China, and it was reportedly much appreciated by the ancient Greeks and Romans. 

The Romans used highly artificial methods of growing the cucumber when necessary to have it for the Emperor Tiberius out of season. Columbus brought the cucumber to the New World, along with many other vegetables. He had them planted in Haiti in 1494, and possibly on other islands. Most of the distinct types of cucumber grown today were known at least 400 years ago. Present forms range from thick, stubby little fruits, three to four inches long, up to the great English greenhouse varieties that often reach a length of nearly two feet.

2.3.3. Cultivation and Harvesting
The cucumber responds like a semitropical plant. It grows best under conditions of high temperature, humidity, and light intensity and with an uninterrupted supply of water and nutrients. Under favourable and stable environmental and nutritional conditions and when pests are under control, the plants grow rapidly and produce heavily. The main stem laterals, and tendrils grow fast. They need frequent pruning to a single stem and training along vertical wires to maintain an optimal canopy that intercepts maximum light and allows sufficient air movement. Under optimal conditions, more fruit may initially develop from the axil of 4 each leaf than can later be supported to full size, so fruit may need thinning.

    Excessive plant vigour is indicated by: rapid growth, thick and brittle stems large leaves, long tendrils, deep green foliage, profusion of fruit, and large, deep yellow flowers. On the other hand, cucumbers are very sensitive to unfavourable conditions like low humidity, and the slightest stress affects their growth and productivity. Because fruit develops only in newly produced leaf axils, major pruning may be needed to stimulate growth. The removal of entire weakened laterals is more effective than snipping back their tips. For an early crop, the cucumber seeds are planted indoors for about 3weeks before they are transplanted. Ideally, soil should be loamy with a neutral or slightly alkaline pH of 7.0 (Mangila et al., 2007 and Enujeke et al., 2013).

    Cucumber crop matures within 40 - 50 days and harvesting starts 45 - 55 days after planting. Harvest is during summer depending on the planting time and variety and a mechanical harvester is being used, mainly for the pickling industry, fresh consumption cucumbers should be harvested at 2-4 day intervals, when the fruits have reached desired size, to avoid losses from oversized and over-mature fruit. Over mature cucumbers left on the vine inhibit new fruit set. Pickling types are harvested when fruits are 5-7.5 cm (2-4 inches) long and slicing types (for fresh market) - when fruits are dark green, firm, 15-20 cm (6-8 inches) long with a diameter of 4-5 cm (1½ - 2 inches) (Okonmah, 2011).

2.3.4. Diseases and Pests associated with cucumber
There are several diseases and pests (aphids, lea beetles, spider mites, squash bugs, pickleworms, cucumber beetles) that pose a threat to the cucumbers and they are mostly fungi-related diseases and pests. They include the Anthracnose (Colletotrichum obicuare), Downy mildew, Powdery mildew, Gummy stem blight, Alternaria leaf spot, and Angular leaf spot, scab (Cladosporium cucummerinum) and Cercospora leaf spot (Rohrbrach et al., 2003).    

The common is the Downy mildew that is caused by the fungus Pseudoperonospora cubensis. It survives more under moist conditions and causes small yellowish area on the upper surface of leaves. And as lesions expand, they become brown with irregular margins and the affected leaves may wither and die. The Alternaria leaf spot that is caused by the fungus called Alternaria cucumerina. This disease is prevalent in growing areas where temperatures are high and rainfall is frequent. They cause small yellow-brown spots with a yellow or green halo which first appear on the oldest leaves. As the disease progresses, lesions expand and become large necrotic patches and leaves begin to curl and die (Rohrbrach et al., 2003).

    Another one is the Gummy stem blight which is a stem and leaf disease to cucumbers caused by the fungi Didymella bryoniae. This fungus also causes a fruit rot called black rot. Here the leaves are covered with brown spots and then the stems may split to form cankers which release a brown gummy substance. Infected stems, seedlings and individual spines may be killed while the affected fruits have irregular circular spots. The Angular leaf spot is caused by a bacterium called Pseudomonas lachrymans and it spreads through infected seeds, splashing rain, insects and movement of people between plants. This bacterium can be present in debris for about 2½years. It causes small water soaked lesions on leaves which expand between leave veins and become angular in shape and as the disease progresses, the lesions turn tan.

    These diseases can be prevented or minimised by using plant certified disease-free seeds, crop rotation, preventative fungicide application, selection of varieties that have some degree of resistance to these diseases, keeping the garden or farm and surrounding area of cultivation free of weeds that could harbour insects that aid in the spread of diseases and also the removal of debris from the farm or garden after harvest (Dent, 1995).

2.3.5. Nutritional values
Cucumbers are good sources of phytonutrients such as flavonoids, lignans and triterpenes, which have antioxidant, anti-inflammatory and anti-cancer benefits. Their health benefits include:
1.    They contain 95% of water which makes them an ideal hydrating fruit.
2.    They contain an anti-inflammatory flavonoid called fisetin which helps in the brain health.
3.    They also contain polyphenols called lignans which help to lower the risk of breast, uterine, ovarian and prostate cancers.
4.    They help in the reduction of unwanted inflammation by preventing the activity of pro inflammatory enzymes.
5.    They are low in calories and high in fibre which makes them useful for both weight loss and digestive health (Huang et al., 2009).

2.4. PINEAPPLE
2.4.1. Introduction

Table 3: Scientific Classification of Pineapple
Kingdom:     Plantae
Order:         Poales
Family:     Bromeliaceae
Subfamily:     Bromelioideae
Genus:     Ananas
Species:     comosus
(Source: Coppens d’Eeckenbrugge and Leal, 2003)