Bacteriological quality of raw milk marketed in and around Guwahati city, Assam, India

Abstract

Background and Aim: Milk is a highly perishable commodity, which is subjected to various types of contamination right from the farm level to the consumers' table. This study aimed to assess the quality of raw milk sold in and around Guwahati city based on the microbial load. Materials and Methods: A total of 200 raw pooled milk samples collected from 25 different locations in and around Guwahati city were subjected to quality evaluation based on the methylene blue reduction test (MBRT), standard plate count, and coliform count as per the standard procedure. Results: Out of the 200 samples evaluated, more than 50% of them were graded as poor to very poor quality based on the MBRT results. None of the samples could be graded as excellent quality and only 14.5% were graded as good quality. The standard plate count and coliform count of all the raw milk samples were found to be significantly higher than the legal standard. A highly significant (p<0.01) difference was observed for standard plate count and coliform count among the different locations in and around Guwahati city. Conclusion: From the present study, it could be inferred that raw milk sold in most parts of Guwahati city do not confer to the legal microbiological standard and may pose a high risk of milk-borne illness among consumers of the city, which needs a systematic series of actions to be implemented properly.

Keywords

• coliform count
• methylene blue reduction test
• raw milk
• total viable count