Physicochemical And Microbiological Quality And Safety Of Raw And Pasteurized Milk Produced And Sold In Bishoftu, Ethiopia

Abstract

Due to its high nutrient content and water activity, milk is prone for adulteration and contamination of copious and heterogeneous number of microorganisms. The present study aimed to evaluate the physicochemical and microbiological quality and safety of raw and pasteurized milk produced and sold in Bishoftu, Ethiopia. A total of 96 raw and pasteurized milk samples from dairy farm, vendors, collection centers, factory, and supermarket were collected. Three brands of pasteurized milk (Holland dairy, Mama & Prime) were considered for the present study. All milk samples were analyzed for physicochemical and microbiological quality and safety. The overall mean physicochemical composition of raw milk collected from different source were fat (3.49±0.09 %), protein (3.07±0.06 %), solid not fat (7.07 ±0.17 %), specific gravity (1.027±0.00 kg/l), add water (9.09±1.85%), titratable acidity (0.16 ±00 %) and pH (6.61±0.02). The mean fat (3.97±0.16) and solid not fat (7.70±0.29) sample from dairy farm was significantly higher than vendors and collection centers. The overall mean of pasteurized milk were fat (3.08±0.09%), protein (2.94±0.06 %), solid not fat (6.83 ±0.17 %), specific gravity (1.026±0.00 kg/l), add water (15.91±1.85%), titratable acidity (0.16 ±00 %) and pH (6.64±0.02).The overall mean aerobic mesophilic bacteria count of raw milk were log10 cfu/ml (6.35±0.10), total coliform count (4.20±0.18), spore-forming bacteria count (2.09±0.10), yeast and mold (3.25±0.16), E. coli (1.19±0.06) and staphylococcus count (2.97±0.12). The mean aerobic mesophilic bacteria count of raw milk collected from vendors during fasting season log10 cfu/ml (6.87±0.24) was significantly higher than dairy farm. The overall mean of pasteurized milk were (log10 cfu/ml) aerobic mesophilic bacteria count (4.47±0.10), total coliform count (2.05±0.18), spore forming bacteria count (2.09±0.10), yeast and mold count (2.00±0.16), E. coli (0.61±0.06) and staphylococcus count (2.27±0.12). The mean aerobic mesophilic bacteria count of pasteurized milk collected from Prime during non-fasting season (log10 cfu/ml 3.59±0.23) was significantly lower than Mama and Holland dairy brands. The prevalence of salmonella in the present study was 10.41% from raw milk while 0% in pasteurized milk. From this study it is possible to conclude that the physicochemical and microbiological quality and safety of raw milk collected from collection centers and vendors were poor, whereas Mama brand of pasteurized milk was substandard. Therefore, implementing strict milk quality control system and mandatory dairy product specification standard should be in place.