AN INVESTIGATION OF ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS PRESENCE IN DAIRY PRODUCTS

1.1 Introduction

Dairy products or milk products are a type of food produced from or containing the milk of mammals, most commonly cattle, water buffaloes, goats, sheep, and camels. Dairy products include food items such as yogurt, cheese and butter. A facility that produces dairy products is known as a dairy or dairy factory. Escherichia coli are part of the normal human intestinal flora. E. coli has been studied intensively in genetics and molecular and cell biology because of its availability, its small genome size, its normal lack of pathogenicity (disease-causing ability), and its ease of growth in the laboratory. Staphylococcus aureus is a Gram-positive, round-shaped bacterium, a member of the Firmicutes, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin.

As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Research Questions and Hypothesis, Scope of work, Limitations of the Study and Definition of technical terms.

1.2 Background of Study

Dairy products are various products derived from cow's milk or that of other female mammals such as goat, sheep, yaks, horses, camel. Dairy products include yoghurt, nono (fermented cow's milk, madara (unfermented cow's milk, cheese, whey, condensed and evaporated milk.) (cultureforhealth, 2015).

Yoghurt, nono, Madara has become so highly valued in humans diet because of their nutritional values and their culinary possibilities (George and pamplon, 2006) Yoghurt is made by controlled thermoduric fermentation of pasteurized non-fat or low fat milk carried out around 45% (Prescott et al., 2005) . It is probably the most popular fermented milk in Nigeria. Yoghurt is a foods produced by bacterial fermentation of milk and these bacteria are known as “yoghurt cultures. Fermentation of lactose by these bacteria produces lactic acid which acts on milk and protein to give yoghurt its texture and characteristic tang. Also yoghurt is made by inoculating certain bacteria (starter culture) usually Streptococcus thermopiles and Lactobacillus bulgaricus into milk, after inoculation, the milk is incubated at 40 to 46% (105 to 115%) until fermentation, the milk is coagulated by bacteria to produce lactic acid (serre et al., 2009)

Nono is an opaque white to milky coloured, liquid food drink gotten from fermented raw cow milk made locally (Godwin and Emmanuel, 2013). It is widely consumed in many African countries including Nigeria. Nono is of two types such as kindirimo and sallah though the nono is mostly termed kindirimo. Mostly the Fulani's produce milk locally in Nigeria and the excess of the milk is processed into these products for preservation and use (Akinyele, et al., 1999). Also kindirimo is produced locally by pasteurized cow milk which are prepared by heating to boiling and then allowed to cool at 37c and the milk butter from the previous day is added to it at the rate of 0.5-1% of the amount of milk to be processed and then left overnight to become sour until it coagulate (Odunfa, et al., 1988)

Madara is the unfermented raw milk collected from cow's under while nono is product form raw Milk collected from cow's udder into a container called calabash and allowed to ferment naturally for 24hours. Nono is also more popular in term of public consumption than madara, this is because madara is rarely sold to public for direct consumption as compared to nono. Madara is produced in homes especially in villages where producers are ignorant of shelf-life and safety standards of the products nono is sold to both rural and urban dwellers as food (Uzeh, et al. 2006).

1.3 Statement of the Problem

Milk is a highly nutritious food that serves as an excellent growth medium for a wide range of microorganism. Milk and its' derivatives are considered vehicle of Staphylococcus aureus for human infections and enteropathogenic Escherichia coli. The microbiological quality of milk and dairy products is influenced by the initial flora of raw milk, the processing conditions and post —heat treatment contamination. Undesirable microbes can cause spoilage of dairy products including Gram-negative psychrotrophs, coliforms, lactic acid bacteria, yeast and moulds. Of concern to public health is the contamination of these dairy products by enterotoxigenic strains of staphylococcus aureus and strains of diarrheagenic Escherichia coli in these dairy products. For this purpose emphasis will be laid on Staphylococcus aureus and Escherichia coli contamination in some diary product and to provide safety measure as a result of poor hygiene practiced by handlers of these products.There is a misnomer in the condition surrounding the sale of some dairy products such as yoghurt, Nono, madara in Makurdi Metropolis. Vendors carry the products from manufacturers without making provision for maintenances of appropriate temperature and sanitary control. This predisposes these products to post production contamination which poses danger to public health.

1.4 Aim and Objectives of the Study

The aim of the study is to investigate the presence of staphylococcus aureus and escherichia coli in dairy products. In achieving this aim the following specific objectives were laid out as follows:

1. To isolate and identify Staphylococcus aureus and Escherichia coli present in Yoghurt, Nono and Madara.
2. To determine the most predominant of the above mentioned organisms in Yoghut, Nono and Madara.
3. To determine the antimicrobial susceptibility of the above isolated organisms.

1.5 Research Questions

The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:

• Are Staphylococcus Aureus and Escherichia Coli present in dairy products?
• Does Staphylococcus Aureus present affect dairy products?
• Does Escherichia Coli present affect dairy products?
• Does staphylococcus Aureus and Escherichia Coli affect the body system negatively during daily product intake such as; milk?

1.6 Research Hypothesis

In order to pursue the objective of this study, the following generalized statements have been designed to guide and aids in obtaining the result for the experiment to be conducted. For this work, the null hypothesis will be represented with H0 while the alternative hypothesis will be represented with hypothesis H1.

Hypothesis One

• H0: The presence of Staphylococcus Aureus and Escherichia Coli does not affect the body system.
• H1: The presence of Staphylococcus Aureus and Escherichia Coli affects the body system.

Hypothesis Two

• H0: There is no Staphylococcus Aureus and Escherichia Coli in dairy products.
• H1: There is Staphylococcus Aureus and Escherichia Coli in dairy products.

1.7 Justification / Significance of the Study

Since dairy products are widely consumed as food, this study will help to establish contamination by Staphylococcus aureus and Escherichia coli, mode of contamination and thus aid in determining their safety for consumption. The result of this study will also help in providing information on these products by the producers, which will promote healthier handling of the product by the producers, the sellers and the consumers. It will also reveal the health implication of their consumption, since they are very delicious and nutritious drink.

1.8 Scope of the Study

The study focuses on the investigation of the presence of staphylococcus aureus and escherichia coli in milk products (viz; Dahi, Ice cream, Gulabjamun, Burfi, Khoa, and Butter) in Owerri, Imo State.

1.9 Limitations of the Study

During the course of this study, many things militated against its completion, some of which are:

1. Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
2. Establishment Policies: Establishment policies posed a serious limitation as most staffs are not ready to release information needed for this project work. There were lots of information needed from the staffs of this establishment to enhance the study which took them time to release or they did not release at all for security purposes, hence the scope was reduced.
3. Research material: availability of research material is a major setback to the scope of the study.
4. Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
5. Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection.

1.10 Definition of Terms

E.coli: Is an acronym for Escherichia coli which is a bacterium commonly found in the intestines of humans and other animals, some strains of which can cause severe food poisoning.

Staphylococcal: Staphylococcus (staph) is a group of bacteria. There are more than 30 types. A type called Staphylococcus aureus causes most infections. Staph bacteria can cause many different types of infections, including; skin infections which are the most common types of staph infections.