1Department of Veterinary Public Health and Epidemiology, MR College of Veterinary Science and Research Centre, Jhajjar-124 109, Haryana, India.
2Department of Veterinary Public Health and Epidemiology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781 001, Assam, India.
3Department of Veterinary Biochemistry, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781 001, Assam, India.
4Department of Livestock Products Technology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781 001, Assam, India.
Raw milk is a highly nutritious food but also an excellent medium for microbial growth if hygienic handling and cold chain practices are inadequate. In informal dairy supply chains, contamination may occur during milking, storage, transportation and retail sale, posing food safety and public health risks. Standard plate count (SPC) and coliform count are widely used indicators of overall microbial load and sanitary quality of milk. This study assessed the bacteriological quality of raw milk from rural cattle farms and urban milk selling points in Kamrup District, Assam, India (26.22°N, 91.65°E) and compared the microbial status between rural and urban sources.
A total of 450 raw milk samples were collected, including 225 samples from 75 rural cattle farms (three randomly selected cows per farm) and 225 samples from 75 urban milk selling points (three pooled milk samples per point). Each sample (50 mL) was collected aseptically in sterile, labelled containers and transported to the laboratory under maintained cold chain conditions. Samples were stored at 5°C and processed within 3–4 hours of collection. SPC and coliform counts were determined by pour plate technique using nutrient agar and Violet Red Bile Agar (VRBA), respectively. Colony counts were expressed as log cfu/mL. Rural and urban means were compared using Welch’s independent samples t-test in R (version 4.4.2), with p<0.05 considered statistically significant.
Both rural and urban milk samples showed very high microbial loads. SPC ranged from 10.62-13.63 log cfu/mL in rural samples and 10.80-13.63 log cfu/mL in urban samples, while coliform counts ranged from 6.49-7.26 log cfu/mL (rural) and 6.49-7.24 log cfu/mL (urban). No statistically significant differences were observed between rural and urban sources for SPC (p = 0.9987) or coliform count (p = 0.9438). Overall microbial indicators substantially exceeded permissible limits, indicating poor hygienic quality of raw milk in the study area and underscoring the need for strengthened hygiene practices, monitoring and cold chain maintenance across the milk supply chain.
Coliform, Kamrup, Milk samples, SPC
