Abstract:
Milk is a highly nutritious substance that contains macro and micronutrients such as fats, proteins,
carbohydrates, vitamins, minerals, and active compounds that have a role in health protection.
However, the quality of milk at Bahir Dar city was not properly investigated so far. Therefore, the
current study was aimed to assess the quality of raw cow milk samples, which were collected from
some selected districts of Bahir Dar city administration such as Ayer Tena, Ghion, and Kobel. For
mineral content determinations, 5 mL of each sample was digested on the digestion block with a
mixture of 5 mL of 69-70% HNO3 and 2 mL of 30% H2O2 until a colorless solution appeared. The
physicochemical properties, concentration of metals, and microbial quality in milk samples were
measured by the lacto scan milk analyzer, flame atomic absorption spectrophotometer and BOD
Incubator, respectively. Mn, Pb, and Cd were below the detection limits of the instrument while all
metals (Ca, Mg, Na, K, Fe, Zn, and Cu) were measured in all studied areas. The mean contents of
physicochemicals in the rage of pH (5.68 - 5.81), SG (1.026 – 1.032 g/ml), TA (0.21 - 0.27 %), FP
(-0.547 to -0.590 0C), TS (8.57– 12.32 %), Protein (2.13 – 2.87%), Fat (2.76 – 4.68 %), SNF (5.81-
7.84%), Lactose(3.19 - 4.31%), Ash contents(0.47-0.64%), Added water (4.22-5.63%); the
concentrations of detected metals in the rage of Ca (855.75 – 1038.5), Mg (146.5 – 152.7), Na
(832.6 – 919.3), K (1029.4 – 1232.6), Fe (0.95 – 1.12 mg/l), Zn (1.43 – 3.30), Cu (0.48 – 0.68 mg/l)
and microbial quality in the rages of CC (1.81-1.96 log10 cfu/ml) and TBC (4.49-4.64 log10 cfu/ml)
in the studied areas , respectively . The validity of the method of the analysis was confirmed by
recovery test and the result was in the range from 87.5 to 95%. Each metal concentrations,
physicochemical contents and microbial quality were compared with guidelines of different
international organizations and literatures. Therefore, except milk fat, all physicochemical
parameters were below the international standard; as well as estimated daily intake values of all
the detected metals are below the recommended dietary allowance values; however, in terms of
microbial quality results, the raw cow milk in this study areas for human consumptions is safe.