Evaluation of the microbial and physicochemical quality of raw and boiled milk selling in selected areas of Sheger City, Oromia

Abstract

The objective of this study was to evaluate milk handling practices, hygienic conditions, and the physicochemical and microbial quality of raw and boiled milk obtained from dairy product shops and cafeterias. A semi structured questionnaire was administered to 205 respondents (95 dairy product shops and 110 cafeterias), and a total of 60 milk samples (30 raw and 30 boiled milk samples) were aseptically collected for microbial analysis, including aerobic mesophilic bacterial count, coliform count, and yeast and mould count, as well as physicochemical quality assessment. The results indicated that 88.24% of dairy product shops and 96.4% of cafeterias used temperature controlled refrigerators for milk storage. Approximately 98.94% of respondents used municipally supplied water for cleaning milk utensils. Plastic containers were the most commonly used materials for milk storage. About 92.3% of respondents in the study areas used raw milk to serve customers, whereas 7.7% used milk powder as a raw material. The majority (82.9%) of dairy product shops sold raw milk, Irgo, Ayib, and butter, while 17.1% sold both raw and boiled milk. The overall mean aerobic mesophilic bacterial counts, coliform counts, and yeast and mould counts for raw and boiled milk were 6.14 and 3.21 Log₁₀ cfu/ml, 4.78 and 2.31 Log₁₀ cfu/ml, and 3.71 and 0.71 Log₁₀ cfu/ml, respectively. Significant differences (p < 0.05) were observed in microbial counts between milk sources in dairy product shops. However, no significant variation was observed in yeast and mould counts among boiled milk samples collected from cafeterias. The physicochemical quality parameters of milk samples from both sources were within acceptable limits; however, the microbial quality was below the required standard. Therefore, strict hygienic practices should be enforced during milk collection, handling, and storage to improve milk quality and protect public health.