Detection and Analysis of Pathogenic Bacteria from Raw and Pasteurized Milk

Abstract

Milk is a proper and complete healthy diet for all individuals. Milk contains all the basic nutrients such as carbon, calcium, and rich water content which facilities bacterial contamination if hygienic conditions are not properly maintained. Different types of bacteria such as gram-positive and gram-negative can contaminate milk in many ways such as use of unclean utensils, storage tanks, and other factors which includes diseased animals, or/and animals suffering from mastitis. Most commonly isolated organisms from raw milk samples are E. coli, Shigella, Staphylococcus aureus, Klebsiella, and spores forming Bacillus species which can cause serious enteric illness if contaminated consumed. Pasteurization process extensively reduces the risk of contamination and makes the milk safer for drinking. In this study, we have collected 24 samples in total of raw milk (n=12) and pasteurized milk (n=12). Further, we processed the milk samples on different agars. For raw milk, we used Nutrient agar, Mannitol salt agar, and Eosin Methylene blue agar whereas for pasteurized milk we have used dye reduction test. Raw milk indicated high contamination as compared to the milk which is pasteurized. Even some locally available pasteurized milk has detected contaminating agents. As the results indicated that raw milk is highly contaminated so for the safety of individuals and the population, it is suggested that we should use pasteurized milk in our daily life. Furthermore, we must apply some safety precautions including maintenance of tanks, storage temperature, and sterilization of utensils in which milk is kept.