Assessing milk quality by evaluating total bacterial count in bulk milk in selected commercial dairy farms in Chattogram

Abstract

Milk is an essential component in many healthy diets but it may lead to public health risks if contaminated by microorganisms. So, evaluation of the microbiological quality of raw milk is crucial before using it for human consumption. However, limited studies have been prioritized to assess the microbiological quality of bulk milk (BM) on the primary production site in the dairy farms in Bangladesh. For that, a study was conducted on ten selected commercial dairy farms in Chattogram during January 2021 to May 2023. The study aimed to evaluate the microbial quality of BM by assessing the total bacterial count (TBC) and determine the association of risk factors with the microbial quality of raw milk. The data was collected from the enrolled dairy farms through face-to-face interviews while receiving the samples in the laboratory, TBC was estimated following the pour plate technique. The mean value of TBC among 185 samples was 2.7 x 107 CFU per mL, ranging from 4.8 x 104 to 1.5 x 109 CFU per mL. The study finding indicated that most of the BM samples showed a higher bacterial count than a satisfactory level in terms of public health standards (1x 105 CFU per mL). Random-effect generalized linear regression model shows that season (P < 0.001), sampling year (P < 0.001), and herd size (P < 0.20) were associated with an increase in TBC of bulk milk. A significant increase in TBC was observed in summer than in the rainy and winter season. Higher TBC was found in medium-scale farms than in small and large-scale farms. This study revealed that TBC can be influenced by several factors such as, season and herd size therefore, additional hygienic considerations of the farms need to be monitored in future studies to ensure hygienic milk production and public health safety