Analysis of microbiological quality and adulteration of raw milk samples from different areas of Kathmandu Valley


  • Laxmi Parajuli Orcid
  • Subash Paudel Orcid
  • Rama Khadka Orcid
  • Roshani Maharjan Orcid
  • Anima Shrestha Orcid


Milk is a highly nutritious product that is susceptible to degradation due to microbial activity. Maintaining milk quality is crucial and can be achieved by monitoring specific parameters. This helps preserve the nutritive value of milk, which is essential for proper growth and health. Adulteration and improper storage can diminish the nutritional quality of milk. Therefore, this study aimed to assess the microbial load and adulteration of milk samples collected from various regions of the Kathmandu Valley. Sixty raw milk samples were gathered from local dairies (45) and cow farms (15) between April 2019 and July 2019. These samples were evaluated for microbial quality (total plate count, total coliform count, Salmonella spp., Shigella spp., and Vibrio spp.) and adulterants (starch, table sugar, soda, soap, and hydrogen peroxide) following standard guidelines. Out of the total samples, 58.3% (35) exhibited coliform growth, while Shigella spp. and Vibrio spp. did not grow on any media. Among coliforms, Enterobacter spp. was the most prevalent at 33.3%, followed by Escherichia coli at 32%. Antibiotic susceptibility testing revealed that the highest proportion of bacteria was sensitive to Ciprofloxacin and Gentamycin, followed by Ceftazidime. Adulteration analysis indicated that 33.3% and 48.3% of samples were adulterated with sugar and soda, respectively. Starch and soap were not detected in any analyzed samples. The highest titratable acidity (0.16%) was observed in cow farms compared to dairy farms. The findings of this study suggest an urgent need for routine quality testing of milk samples available in the market to prevent the spread of milk-borne diseases and preserve the nutritive value of milk.