Assessment of physicochemical properties and bacteriological quality of raw cow milk along the Dairy Value Chain in Mekelle City, Tigray, Ethiopia

Abstract

Milk's complex biochemistry, high water activity, and nutritional content make it an ideal environment for microbial growth and reproduction. This study evaluated the quality of raw cow's milk, including physicochemical composition and bacteriological load, among dairy value chain operators in Mekelle City. A cross-sectional study design was conducted from December 2023 to June 2024, using 120 raw milk samples (Dairy farm, 80; Vendors, 20; Cafeteria, 20). Laboratory investigations, including physicochemical properties of raw cow milk were evaluated using the Lactoscan milk analyzer. The bacteriological assessments were employed to assess the total bacteriological load and total coliform count at the Microbiology Laboratory of Mekelle University College of Veterinary Science. The milk samples from dairy value chain participants were found with an average fat, protein, lactose, SNF, freezing point, density, and ash, 4.58 ± 0.94%, 3.08 ± 0.27%, 4.58 ± 0.47%, 8.44 ± 0.685%, -0.5395 ± 0.05C0°C, 1.029 ± 0.0029 g/cm³, 0.67 ± 0.061%, respectively. The overall bacterial and coliform counts were 7.23 log10 CFU/mL and 4.5 log10 CFU/mL, (Mean ± S.d) respectively. The primary factors recorded affecting the quality of raw cow milk include limited awareness, poor hygienic standards, a shortage of clean water, inadequate cooling facilities, a lack of quality control systems, and the absence of a payment system based on quality. In this study, milk samples from cafeterias showed the highest mean value bacterial load, followed by vendors, whereas samples from dairy producers had the lowest mean value bacterial load. Therefore, the microbial quality of raw cow milk in the study area was low, and needs awareness creation.