Microbiological profile of milk: Impact of household practices
Amit Agarwal1, Vandana Awasthi2, Ajit Dua3, Sanjeev Ganguly4, Vivek Garg5, Satwinder S Marwaha6
1 Project Fellow, Punjab Biotechnology Incubator, Mohali, Punjab, India
2 Scientist Biology, Punjab Biotechnology Incubator, Mohali, Punjab, India
3 Senior Scientist, Punjab Biotechnology Incubator, Mohali, Punjab, India
4 Head, Medical and Scientific Affairs, Nestlé India Limited, Mohali, Punjab, India
5 Manager Medico Marketing, Nestlé India Limited, Mohali, Punjab, India
6 Chief Executive Officer, Punjab Biotechnology Incubator, Mohali, Punjab, India
Satwinder S Marwaha
Chief Executive Officer, Punjab Biotechnology Incubator, SCO: 7&8 (Top Floor), Phase-V, SAS Nagar (Mohali) 160059, Punjab
Source of Support: The study was conducted with fi nancial support from Nestlé India Ltd., Conflict of Interest: Sanjeev Ganguly and Vivek Garg are employees of Nestlé India Ltd. There are no other confl icts of interest.
Background: Milk is susceptible to contamination by many microorganisms including microbial pathogens responsible for causing diseases. Various processes including pasteurization, boiling or storage under refrigerated conditions are undertaken to minimize the microbial contamination of milk. Objective: This study was undertaken with an objective to evaluate the effect of household practices on the microbiological profile of milk. Materials and Methods: Milk samples of pasteurized, ultra heat treated (UHT) as well as unpasteurized milk (Vendor's milk) were collected. The effect of different storage practices and treatments on the microbiological profile (standard plate count (SPC), coliform, E. coli, Salmonella, Shigella, Staphylococcus aureus, yeast and moulds, anaerobic spore count, and Listeria monocytogenes) of milk was studied using National/ International Standard Test Methods. Results: Average SPC in vendor's milk was found very high as compared to pasteurized milk. Coliform, yeast and moulds, E. coli, and Staphylococcus aureus were detected in the samples of vendor's as well as pasteurized milk. Boiling the milk reduces SPC and kills the other microorganisms. Storage of boiled milk under room temperature or refrigerated condition resulted in a similar increase in SPC at the end of 24 h, but storage of un-boiled milk even under refrigerated conditions increased SPC manifold after 24 h. Conclusion: The pasteurization process and hygienic conditions at the milk processing units along with cold chain of milk from suppliers to end users needs improvement. Currently, even pasteurized milk does not match the microbiological standards. It is recommended that milk should be boiled before consumption and refrigerated for storage to improve its shelf life/keeping quality.