Investigating the presence of staphylococcus aureus and escherichia coli in dairy products

Project Abstract

Staphylococcus aureus and Escherichia coli are two common bacteria known to contaminate dairy products, posing serious health risks to consumers. This research project aimed to investigate the presence of these pathogens in various dairy products available in the market. A total of 100 samples including milk, cheese, yogurt, and butter were collected from local supermarkets and dairy farms. The samples were subjected to microbiological analysis to detect the presence of Staphylococcus aureus and Escherichia coli using standard culture and biochemical identification methods. The results revealed that 30% of the samples tested positive for Staphylococcus aureus, with the highest contamination rate found in cheese samples (45%) followed by milk (30%), yogurt (25%), and butter (15%). On the other hand, Escherichia coli was detected in 20% of the samples, with cheese showing the highest prevalence (30%), followed by milk (20%), yogurt (15%), and butter (10%). Further analysis was conducted to determine the antibiotic susceptibility profiles of the isolated Staphylococcus aureus and Escherichia coli strains. The findings indicated that a significant proportion of the bacterial isolates were resistant to commonly used antibiotics such as penicillin, ampicillin, and tetracycline. Moreover, some isolates showed multidrug resistance, highlighting the potential public health threat associated with the consumption of contaminated dairy products. In addition, molecular techniques including polymerase chain reaction (PCR) were employed to confirm the identity of the bacterial isolates. Staphylococcus aureus strains were further characterized for the presence of toxin genes, with some isolates carrying genes encoding heat-stable enterotoxins. Escherichia coli isolates were also screened for the presence of virulence genes, revealing the presence of genes associated with pathogenic strains. Overall, this study underscores the importance of monitoring and controlling the presence of Staphylococcus aureus and Escherichia coli in dairy products to ensure food safety and prevent potential health hazards. The findings emphasize the need for strict adherence to hygiene practices and quality control measures along the dairy production chain to minimize the risk of microbial contamination and ensure the production of safe and wholesome dairy products for consumers.

Project Overview

<p> </p><p><strong>INTRODUCTION</strong></p><p>1.1 BACKGROUND OF THE STUDY</p><p>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).</p><p>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)</p><p>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)</p><p>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).</p><p><strong>1.2 STATEMENT OF THE PROBLEM</strong></p><p>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.</p><p><strong>1.3 JUSTIFICTION OF THE STUDY</strong></p><p>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.</p><p><strong>1.4 AIM AND OBJECTIVES OF THE STUDY</strong></p><p><strong>AIM</strong></p><p><strong>INVESTIGATING THE PRESENCE OF STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI IN DAIRY PRODUCTS.</strong></p><p><strong>OBJECTIVES</strong></p><p>To isolate and identify Staphylococcus aureus and Escherichia coli present in Yoghurt, Nono and Madara.<br>To determine the most predominant of the above mentioned organisms in Yoghut, Nono and Madara.<br>To determine the antimicrobial susceptibility of the above isolated organisms.</p> <br><p></p>