STUDIES ON THE INCIDENCE AND EVALUATION OF BACTERIA IN PROCESSED AND UNPROCESSED MILK

Shanmugapriya Arunachalam, Bharathi Balasubramanian* and Deepa C Philip

ABSTRACT

Introduction: Milk contain important nutrients such as minerals, vitamins, proteins and lipids and are consumed by all age group of human around the world. Since the presence of nutrients makes it hard to prevent milk from becoming contaminated with microorganisms. The microbial content of milk can be used to judge its quality. Aim: The current study is to identify the incidence and to evaluate the bacteria in processed and unprocessed milk. Methods and Materials: Nine distinct types of milk samples were collected and diluted with selenite F broth, normal saline, and macconkey broth. The samples were grow on blood agar, macconkey agar, nutrient agar, saboraud dextrose agar, thiosulfate citrate bile salt agar and deoxycholate citrate agar and observed for the growth in the form of turbidity following a 24-hour incubation period. Next, the developed organism is identified by biochemical analyses and the gram stain. By measuring the dye reduction time and analysing the milk grade in the samples, the MBRT test is used to determine the quality of the milk. Results: The isolated organisms were E.coli, Kelbsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter, S. aureus, Micrococcus, Bacillus, Spingomonas paucimobils. When compared to processed milk, the unprocessed milk had a higher bacterial burden, indicating the need for appropriate sterilisation before consumption. Conclusion: The results of this study will be useful in evaluating the microbiological safety of both pasteurised and raw milk as well as informing public health risk assessments. Therefore, it is imperative that the control methods be followed in order to increase the microbiological quality of milk.

Keywords: E.coli, Kelbsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter, reductase test, pasteurized milk.