Isolation And Identification Of Bacteria From Food Vendors And Some Vegetable Available
TABLE OF CONTENTS
Table of contents-v
List of tables-vii
1.1 Aim and Objectives-6
2.1 Literature review-7
2.2 Food hygiene-12
2.3 Factors that contribute to food borne illness-13
2.4 Features of common food -borne pathogens-16
2.5 Food-born diseases-25
2.6 Pre-disposing factors to food-born illness-26
2.7 Prevention of food born illness-27
3.1 Materials and method-29
3.1.1 Hard ware-29
3.1.2 Soft ware-29
3.3 Identification of isolates-33
LIST OF TABLES
i. some food borne bacteria and affiliated foods-22
ii. Morphological features of bacteria isolated from the different food samples-40
iii. Total bacterial count (CFU/mg) of street vended foods samplers-43
iv. Biochemical test-44
v. Food samples with their associated-45
Safety of food is a basic requirement of food quality. A total of 25 street food samples (Jollof rice, egwusi soup, ugu, water leaf and green), were randomly purchased from five different vendors in Ogbete main market Enugu. The samples were transported in ice to the laboratory. The samples were bacteriologically analyzed using pour plate technique and sub-culture. Pour plate techniques was done by carrying out serial dilution of the sample after which the first tube and the last tube were picked and 1ml of each sample was pipette into a Nutrient agar, the plate was then incubated for 24 hours at 37oC after which the plate were examined for growth. Sub culture was done using bacteriological agar. All the screened food samples had varying levels of bacterial growth ranging from 1.0 X 105 to 3.0 X 106 cfu/ml. ninety percent of the sampled foods had bacterial counts above the acceptable limits (104 cfu/ml) and 10% of the samples had bacterial counts less than (<104 cfu/ml). Six bacterial species were isolated from the foods sampled. Staphylococcus aureus, Bacillus cereus, Vibrio spp, Salmonella spp, Escherichia coli and Shigella spp. More than one pathogenic micro organism were isolated from jollof rice and water leaf. The findings revealed that street foods are potential vehicles for transmitting foodborne illnesses thus the need to develop practical strategies geared toward street food safety. CHAPTER ONE
Bacterial are group of microorganism all of which lack a distinct nuclear membrane (and hence are considered more primitive than animal and plant cells) and most of which have a cell wall of unique composition. Most bacteria are unicellular; the cells may be spherical (cocci) rod-shaped (bacillus), spiral (spirillum), comma-shaped (vibrio) or corkscrew-shaped (spierocheate). Generally, they range in size between 0.5 and 5um. (Elizabeth and Martin, 2003).
Food is any substance that people or animal eat or drink or that plants absorb to maintain life and growth. Food is any substance consumed for nutritional support for the body; it is usually of plant or animal origin. (Ezeronye, 2007). Food consists of chemical compounds which heterophilic living thing consumes in order to carry out metabolic processed. They are also substances which when introduced to the digestive system under normal circumstances contribute to growth, repair and production of energy.
(Ezeronye, 2007). Foods are classified into six essential nutrients known as protein, carbohydrate, vitamin mineral, fat and oil, water.
PROTEIN:-One of a group of organic compounds of carbon, hydrogen, oxygen and nitrogen (sulphur and phosphorus may also be present). The protein molecule is a complex structure made up of one or more chains of amino acid, which are linked by peptide bonds. Proteins are essential constituents of the body; they form the structural material of muscles, tissues, organs, etc. and are equally important as regulators of function, as enzymes and hormones, proteins are synthesized in the body from their constituent amino acids, which are obtained from the digestion of protein in the diet (Elizabeth and Martin, 2003).
CARBOHYDRATE:-One of a large group of compounds, including the sugar and starch, that contain carbon, hydrogen and oxygen and have the general formula CX (H20) Y-Carbohydrates are important as a source of energy: they are manufactured by plants and obtained by animals from the diet, being one of the three main constituent of food. All carbohydrates are eventually broken down in the body to the simple sugar glucose which can then take part in energy producing metabolic processes. Excess carbohydrate, not immediately required by the body is stored in the liver and muscles in the form of glycogen. In plants carbohydrate are important structural materials (e.g. cellulose and storage products (commonly in the form of starch). (Elizabeth and Martin, 2003).
VITAMIN:-Any of a group of substances that are required in very small amounts, for healthy growth and development: they cannot be synthesized by the body and are therefore essential constituents of the diet. Vitamins are divided into two groups, according to whether they are soluble in water or fat. The water soluble groups include the vitamin C; the fat soluble vitamins are vitamins A, D, E and K. Lack of sufficient quantities of any of the vitamins in the diet results in specific vitamin deficiency diseased (Elizabeth and Martin, 2003).
FAT:-A substance that contains one or more fatty acids (in the form of triglyceride) and is the principal form in which energy is stored by the body (in adipose tissue). It also serves as an insulating material beneath the skin (in the subcutaneous tissue) and around certain organs (including the
kidney). Fat is one of the three main constituents of food; it is necessary in the diet to provide an adequate supply of essential fatty acid and from the efficient absorption of fat -soluble vitamins from the intestine. Excessive deposition of fat in the body leads to obesity. (Elizabeth and Martin, 2003).
A vendor is a person selling something (en.Wikipedia org/Wiki/vendor). The world Health Organization (WHO) Indicated that food-borne diseases most of which are of microbial origin are perhaps the most widespread problems in the contemporary world and this is responsible for about one third of death worldwide, through infectious conditions with adverse effects can reduce economic productivity. Poor sanitary condition in most of the local markets and the environment being highly polluted and charged with spoilage and pathogenic flora is likely the source of contamination of food items sold by such vendors. (Oweghe et al., 2001). It is known that poor hygienic conditions in a food environment may encourage the multiplication of pathogenic organisms in food (Egeonu, 2002). It has been observed that Bacillus cereus and Staphylococcus aureus grow to oxygenic levels in food at 300c (Egeonu, 2003). Therefore microbiological examination of foods and food contact surfaces may provide information concerning the quality of the raw food, and the sanitary conditions under which the food is processed (Michael et al; 2004). Microorganisms live throughout the kitchen and can easily move around by attaching themselves to people easily move around by attaching themselves to people, food and equipment. Bacteria may pass from equipment to food which has not been properly cleaned and sanitized before being used to prepare another food. Examination of food consumed and also wholesomeness. This implies that the food to be consumed by humans should be pure and free from contamination especially by pathogenic and spoilage microorganisms. Failure to ensure the safety and wholesomeness of the food consumed by the public might lead to some illness. To reduce contamination by microorganisms to a minimum level, and obtain good keeping quality of the products, the raw materials should regularly be monitored and examined.
Food contacts surfaces are a major concern for food service facilities in controlling the spread of food-borne pathogens, surfaces such as bench tops, table, etc. may have bacterial on them from contact with people, raw foods, dirty equipments or other things such as cartons that have been stored
on the floor. If the bench tops are not properly cleaned, any food on them will be contaminated by the bacterial (Kamil, 2005).
The overall aim of this work is to access selected foods sold by vendors in Ogbete main market Enugu for bacterial contamination.
1. To isolate and identify bacterial species associated with food contamination.
2. To determine the microbial load of isolated bacteria.
3. To establish the public health implication of consumption of such foods.