ASSESSMENT OF THE PHYSICOCHEMICAL QUALITY AND MINERAL COMPOSITIONS OF RAW COW’S MILK COLLECTED FROM MILK PRODUCER IN HAWASSA, SIDAMMA REGION, ETHIOPIA

Abstract

Milk is a wholesome food as it contains various nutrients. Milk should be free from contaminants and adulterant materials that can directly or indirectly affect the consumer‘s health. It is, therefore, necessary to check the safety and quality of milk available in the domestic market. Therefore, this study was aimed at determining the levels of selected physicochemical quality parameters and metals in raw cow‘s milk samples collected from milk producer, in Hawassa city, Sidamma Region, Ethiopia. The determination of fat, Solids-Non-Fat, milk density and added water to milk were carried out using EKOMILK Ultrasonic Milk Analyzer, in Hawassa University, and the total moisture and total ash content in raw cow milk samples were done using the Gravimetric Method. The values of total protein, total solids, and lactose content of the raw cow‘s milk samples were calculated using formulae that used the measured value of Solids-NonFat, while the metal content were determined by flame atomic absorption spectrometry (FAAS). The average values of the physicochemical parameters investigated in this study were found to be in the range pH (6.59–6.73), water added (5.54–10.33)%, density (1.023–1.029) g/mL, titratable acidity (0.153–0.213)%, total solids (10.566–13.800)%, total ash (0.603–0.636)%, Solids-not-fat (SNF) (7.266–7.666)%, total fat (3.266– 6.230)%, total protein (2.666–2.813)%, and lactose (3.996– 4.216)%. The average concentrations of the metals were found to be in the range Ca (1124.770–1505.110) mg/L, Mg (102.330–109.000) mg/L, Cu (0.0536–0.0817) mg/L and Mn (0.052–0.072). Metals such as Ni, Co, Cr, and Pb were found to be below the detection limit of the instrument. The accuracy of the method of the analysis was evaluated by analyzing the digest of the spiked samples and the recoveries of the metal were in the range of 99.810– 104.220%. One-Way-ANOVA analysis showed that there were significant variations (p < 0.05) in the physicochemical quality parameters, and metal content except for total ash, solids-non-fat, total protein, and lactose among the raw cow‘s milk samples. In general, pH, specific gravity, titratable acidity, total ash, and lactose were found to be within the maximum permitted level set by Ethiopian Standard, and EU guidelines, while total fat, total protein, and solid-not-fat were found to be below the recommended limits.