環境および分析毒性学

Chemical Composition and Heavy Metals Analysis of Raw Cow��?s Milk

Abstract

Endale Tesfaye Damtew and Aregay Berhe Gebre

The study was primarily aimed at determining physicochemical quality, minerals and nutrient composition of cow’s milk samples collected from different areas of Nuer Zone and Gambella town, Ethiopia. A total of 6 cow’s milk samples from farmers and vendors (dairy cooperative milk collection centers and small shops) were collected. All samples were collected using proportional random sampling method. The presence and concentration of various minerals (such as Na, Ca, Mg, P and N2 ) and heavy metals (Cd, Cr and Pb) were determined. Different physicochemical parameters of milk samples such as pH, titratable acidity and density were examined. The proximate chemical compositions of milk samples such as moisture, protein, fat, solids-not-fat (SNF), lactose, total solid and ash contents also were determined. The mean values of pH, moisture, titratable acidity, protein, fat, solids-not-fat, ash, total solid, density and lactose contents of milk samples collected from farmers are 5.22, 86.99%, 1.01%, 3.46%, 4.80%, 6.23%, 0.04%, 11.04%, 1.01 g/cm3 and 4.43%, respectively. On the other hand, the respective mean values of physicochemical parameters of vendors’ milk samples are 5.09, 88.85%, 2.10%, 3.76%, 4.88%, 7.07%, 0.591%, 11.91%, 1.02 g/cm3 and 4.70%. The results of the study showed that mineral compositions of all collected milk samples are adequate. The contents of heavy metals are below maximum permissible limit as compared with standard levels. However, Most of the milk samples have poor physiochemical quality; they have high titratable acidity values and low pH values which are beyond the permissible ranges. This indicated that milk samples, in particular, samples from vendors are not followed good milk handling practices, and they need improvement. The obtained proximate analysis results revealed that all the collected milk samples fulfilled the WHO and other national and international standards except lactose and protein contents.