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The Project File Details
The analysis was carried out to determine the microbial load on spoilt egusi. The Total heterophilic bacteria recorded ranges from 1.2 X 1010 – 2.8 X 1010 Cfu/g and the Total coliform count ranges from 7.8 X 109 – 9.8 X 109Cfu/g and the Total fungi obtained ranges from 1.6 X 1010 – 1.7 X 1010 Cfu/g. Five genera of bacteria were isolated which are salmonella, Staphylococcus, Escherichia coli, Bacillus, and Klebisiella. Fungal isolates are Rhizopus spp., Aspergillus spp., mucor spp., and Penicillium spp.
1.0 INTRODUCTION/LITERATURE REVIEW
1.1 BACKGROUND OF STUDY
Citrullus colocynthis l. “Egusi” is specie of melon, native to tropical Africa (west of the east Africa rift) where it is grown for food and as a source of oil.
Biochemical changes in food when observed as undesirable is considered as spoilage because food is an important source of nutrients, microorganism inhibit and grow in them which gradually changes their quality and their natural properties. Deterioration of food generally is attributed, two main causes which are natural degradation due to activities of enzymes and growth of microorganisms (bacteria, mould and yeast). The negative effects of these microbial activities results in decay, rotting of food and food poisoning. Food spoilage occurs when microorganisms release their enzyme and absorbs the nutrients of the food. The detection and control of pathogens responsible for food spoilage is a part of food microbiology. The population of microorganisms and their types present in food are determined by the environment the food is originally obtained.
1.2 STATEMENT OF PROBLEM
Microorganisms are known to be harmful and destroy foods such as fruit and vegetable, thereby reducing the quality, quality for man’s consumption and also desirable profits from sales of producers of food.
Bacterial and fungal are very harmful microorganisms which are associated in many plant diseases and spoilage. The adverse effect of bacteria and fungal has resulted in the shortage of Egusi for consumption and also reduced its nutitional valve.
1.3 AND OBJECTIVE OF THE STUDIES
The aims and objective of this topic; Microbial profile of spoilt Egusi “Citrullus colocynthis l.” are as follow:
To determine the microbial load of spoilt Egusi
To isolate the microorganism associated in the spoilage of Egusi.
To identify and characterize the isolated organisms.
1.4 SIGNIFICANCE OF STUDY
This study will be useful to farmers, melon industries and consumers of Citrullus colocynthis l. The outcome of this research will guide user of Egusi, on the best methods of preserving it, to avoid spoilage.
The research work Citrullus colocynthis l. for student project work, to farmers seeking to know more about Colocynthis citrullus l. and to companies that uses it as raw materials for production of oil and food condiment.
1.5 LITERATURE REVIEW
Citrullus colocynthis l., with many common names including colocynth, bitter apple, bitter cucumber, desert gourd, egusi, vine of Sodom, or wild gourd, is a desert viny plant native to the Mediterranean Basin and Asia, especially Turkey (especially in regions such as İzmir), Nubia, and Trieste. It resembles a common watermelon vine, but bears small, hard fruits with a bitter pulp. It originally bore the scientific name Colocynthis citrullus l. (Eidi et al., 2015).
Egusi Citrullus colocynthis l. is a species of melon native to tropical Africa (west of the east Africa rift) where it is grown for food and as a source of oil. It is also known as white melon seed.
Citrullus colocynthis manni is a member of the cucurbitaceae family. This crop is often referred to as “Egusi” given to its long history in West Africa, dating back 4000 years. This plant is basically harvested for its large white seeds called Egusi-itoo. The seeds are commonly processed into soups and oil products and also eaten individually as a snack.
If produce climbing vines up to 4 meters long which are covered in stiff hairs. Then it bears small yellow male and female flowers with petals under a centimeter in length, the heart, shaped or roughly palmate leaves are up to 12 centimeter long and 14 centimeter wide. The fruit is egg shaped, up to about 18 centimeter long and 8 centimeter wide, and cream in colour with green streaks. The fruit and white seeds are edible. Colocynthis citrullus can survive in harsh climates and high yields are attainable in barren landscape.
The roots are large, fleshy, and perennial, leading to a high survival rate due to the long tap root. The vine-like stems spread in all directions for a few meters looking for something over which to climb. If present, shrubs and herbs are preferred and climbed by means of axiliary branching tendrils (Lloyd and John, 1898).
The flowers are yellow and solitary in the axes of leaves and are borne by yellow-greenish peduncles. Each has a sub-campanulated five-lobed corolla and a five-parted calyx. They are monoecious, so the male (stamens) and the female reproductive parts (pistils and ovary) are borne in different flowers on the same plant. The male flowers’ calyx is shorter than the corolla. They have five stamens, four of which are coupled and one is single with monadelphous anther. The female flowers have three staminoids and a three-carpel ovary. The two sexes are distinguishable by observing the globular and hairy inferior ovary of the female flowers (Lloyd and John, 1898).
The fruit is smooth, spheric with a 5– to 10-cm-diameter and extremely bitter taste. The calyx englobe the yellow-green fruit which becomes marble (yellow stripes) at maturity. The mesocarp is filled with a soft, dry, and spongy white pulp, in which the seeds are embedded. Each of the three carpels bears six seeds. Each plant produces 15 to 30 fruits (Citrullus colocynthis, 2012).
The seeds are grey and 5 mm long by 3 mm wide. They are edible but similarly bitter, nutty-flavored, and rich in fat and protein. They are eaten whole or used as an oilseed. The oil content of the seeds is 17–19% (w/w), consisting of 67–73% linoleic acid, 10–16% oleic acid, 5–8% stearic acid, and 9–12% palmitic acid. The oil yield is about 400 l/hectare. In addition, the seeds contain a high amount of arginine, tryptophan, and the sulfur-containing amino acids (Gunideeban, et al., 2010).
Cultivated colocynth suffers of climatic stress and diseases such as cucumber mosaic virus, melon mosaic virus, Fusarium wilt, etc. as any other crop. To improve it, a relatively new protocol for regeneration has been developed with the aim of incorporating disease and stress resistance to increase yield potential and security avoiding interspecific hybridization barriers (Ntui, et al., 2009).
1.5.3 CONSUMPTION AND USES
Citrullus colocynthis l. is primarily grown for the only seeds it produces-seeds are also grounded up and used as major ingredient in cooking soup, stews, it serves as thickener.
It is eaten as protein substitutes. In like Ghana Egusi (Citrullus colocynthis l.) oil is the second prominent cooking oil. The oil is Egusi seeds can be used for cooking, making soaps and for illumination. The flesh of Citrullus colocynthis l. is edible but is not commonly consumed due to its bitter taste. In countries such as Ghana the juice of the fruit is used as healing ointment.
Clinical studies have shown medicinal benefits of colocynth in patients with diabetes, diabetic neuropathy, and hyperlipidemia. In a randomized clinical trial (RCT), HbA1c and fasting blood glucose levels were decreased in patients using 300 mg of C. colocynthis dry fruit powder daily for 2 months. In another trial, intake of 300 mg of powdered seed can lower the triglyceride and cholesterol concentration significantly in nondiabetic hyperlipidemic patients (Rahbar andNabipour, 2010).
Topical C. colocynthis also showed significant efficacy in treatment of patients with painful diabetic neuropathy in another RCT; the application of a topical formulation of C. colocynthis fruit extract can decrease the pain and improve nerve function and quality of life in patients with painful diabetic neuropathy (Heydari, et al., 2015).
Colocynth has been widely used in folk medicine for centuries. Johann Weyer, in De praestigiis daemonum (1563), offers it as a cure for lycanthropy. Interest in its anti-inflammatory properties has been renewed in modern times.
Aqueous and methanol extracts of colocynth showed high antimicrobial activity against Escherichia coli, Staphylococcus aureus, and other bacteria. Extracts of fruits, leaves, roots and stems were also found to be potentially usable against many Gram positive bacilli and fungi such as Aspergillus fumigatus, Aspergillus flavus, and Mucor species.
In addition, some of these extracts were found to have an insulin tropic effect and therefore an antidiabetic effect, which may make them relevant to the treatment of diabetes mellitus (Gurudeeban, et al., 2010).
Cucurbitacin glucosides seem potentially important for therapy against breast cancer cells because of their ability to modify cell morphology and signaling, and to induce apoptosis and changes in mitochondrial membrane potential (Tannin-spitz, et al., 2007).
Another property of colocynth is hair growth stimulation: an experiment on rats demonstrated that hair growth initiation time was significantly decreased after treatment with colocynth petroleum ether extracts (Roy, et al., 2007).
In premodern medicine, it was an ingredient in the electuary called confectio hamech, or diacatholicon, and most other laxative pills; in such cases as required purging, it was very successful. It is one of the most violent purgative drugs known; insomuch that it excoriates the passages to such a degree as to sometimes draw blood and induce a so-called “superpurgation”. Sometimes, it was taken boiled in water, or beer, in obstruction of the menses, which was considered successful in strong constitutions. Some women used it in the same manner, in the beginning of pregnancy, to cause an abortion, which often occurred due to the violence of its operation. Its use for this purpose is documented in ancient times; for example, the following recipe was found in the Ebers medical papyrus in Egypt, dated to about 1550 BCE: (Davis and Company Parke, 1909)
“To cause a woman to stop (terminate) pregnancy in the first, second, or third period [trimester]: unripe fruit of acacia; colocynth; dates; triturate with 6/7th pint of honey. Moisten a pessary of plant fiber [with the mixture] and place in the vagina.”
The powder of colocynth was sometimes used externally, with aloes, etc., in unguents, bandages, etc., with remarkable success against parasitic worms; some, for the same purpose, recommended that the pulp be used as an enema. In iliac passion, enemas of colocynth were used effectively where most other premodern medicines had failed. Troches, or lozenges, made of colocynth were called “troches of alhandal“. They were prepared by cutting the colocynth to a small size, and reducing it to a fine powder in a mortar, rubbed with oil of sweet almonds; adding gum tragacanth, and mastic afterwards. Remedies for counteracting colocynth have included emetics, such as zinc sulfate, and apomorphine, if caught early; later, demulcents and opiates, with stimulants to combat collapse were used (Davis and Company Parke, 1909).
The desert Bedouin are said to make a type of bread from the ground seeds. Some confusion exists between this species and the closely related watermelon (Citrullus ianatus (Thunb)), whose seeds may be used in much the same way. In particular, the name “egusi” may refer to either or both plants (or more generically to other cucurbits) in their capacity as seed crops, or to a soup made from these seeds and popular in West Africa.
The seed flour is rich in micronutrients (vitamins and minerals), and could therefore be used in food formulations especially in regions with low milk consumption such as West Africa. A normal dose of fluid extracted from the fruit pulp is 2 to 5 minims (120 to 310 µl), and for the powdered extract 1 to 2 grains (60 to 130 mg) (Davis and Company Parke, 1909).
Since colocynth is not strongly used as staple food, its seeds might become an interesting source for biofuel production (Citrullus colocynthis, 2012). In addition, colocynth can grow on marginal lands and may improve soil quality as experienced with intercropping. The oil obtained from the seeds (47%) can also be used for medicinal and soap production. The production is not very time- and energy-consuming due to the ability of colocynth to grow on poor soils with just a little moisture and organic fertilizer. The fruits are harvested still unripe by hand, the rind is removed by peeling and the inner pulp filled with seeds is dried in the sun or in ovens. The seeds yield is about 6.7-10 t/ha, which means that for an oil profit of 31-47%, oil yields may reach up to 3 t/ha (Giwa and Solomon, et al., 2010).
1.5.4 SCIENTIFIC CLASSIFICATION
Kingdom – Plantae
Order – Cucurbitale
Family – Cucurbitaceae
Genus – Citrullus colocynthis
Species – C.mannii
1.5.5 GROWING CONDITION
Citrullus colocynthis is propagated entirely by seed. In the transitional zone of west Africa this crop is sown during major rainy season between march and May. Here the soil is rich in organic matter with a high rainfall of 1400mm distributed april – October.
Propagation begins immediately after the first coule of heavy rainfall of the season. Holes around 2cm deep in 1m apart are planted with 3-4 seeds in each. A complete fertilizer should be applied before the propagation, with application of nitrogenrus fertilizer to follow.
Citrullus colocynthis methods contrast in the northern savannahs where conditions are more challenging with low fertility and organic matter. Rainfall in this zone is small at 800mm annually.
Citrullus colocynthis is more successful in this area as a mixed crop, specifically grown in the ridges of sorghum crops, in more challenged areas this crop should be spaced at least 3m apart greatly decreasing per hectare production. After 6-8 months, around September – December the fruit include creamy colour and dried stems and leaves. Each plant average at 2-5 fruits each weighing 0.8 – 1.8 kg and containing 90-400 seeds.
1.5.6 STRESS TOLERANCE
Citrullus colocynthis can survive in nutrient poor soil in climatically diverse areas. The high degree of ground cover from this plant blankets the soil protecting it from sun exposure and water loss, and therefore increases the quality of the soil. The plant can thrive in humid, dry and upland areas with little to no consequence on growth and quality of crop, it is drought tolerant, thriving in west africa’s dry regions adapted to semiarid zones, and is also compatible with warmer tropical high lands.
1.5.7 NUTRITIONAL INFORMATION
The kernel of Egusi seed (Citrullus colocynthis L.) is 44% oil, 30% protein, 10% carbohydrate, 4% ash and 3% fiber.
The oil seed is 64.9% linoleic acid, 12.4% oleic acid, 11.8 % steric acid and 10.9% palmitic acid, vitamins such as thiamin, niacin, B1 and B2 are also prevalent in the seed as well as many micro nutrients. Minerals component are also present in the seed of Egusi which include phosphorus, which is the greatest in number with potassium, magnesium, manganese, sulfur, calcium, iron and zinc too follow. The amino acid content of Egusi (Citrullus colocynthis) makes it a sufficient vegetable protein. There is great need of these seeds as a vital tool for interventions in diseases such as marasmus and kwashiorkor.
1.5.8 MAJOR WEEDS AND PESTS AND DISEASES
Primary issues include the fungus macrophomina phaseolina which attacks the roots and lower stems of the crops causing damping-off disease. The fruit fly species dacus puntifrons may also attack the fruit of this plant. The fruit generally rots due to the presence of larvae. Halticus tibialis is a flea hopper similar to an aphid and may also cause problems for Citrullus colocynthiscrops, often killing the leaves of the plant by sucking out sap. After harvesting many beetle species including the red flour beetle and the cigerate beetle may feed on the seed, which are not properly stored in air tight containers.