Microbiological quality and safety of milk production and marketing in Hawassa district, Ethiopia

Abstract

The microbiological quality and safety of milk samples from different sources in Hawassa distinct from southern nations, nationalities and people regional state was evaluated. A total of 63 raw milk samples were obtained from three selected dairy farms, urban and rural households. Twenty-seven pasteurized milk samples were obtained from three retail brands from various supermarkets in Hawassa city. Each milk sample was collected in triplicate monthly over three months. Total bacterial count (TBC), coliform counts (CC), total staphylococci counts (TSC), yeast and mould counts (YMC) were isolated and identified by morphological and biochemical tests following the standard methods. Household milk samples had a higher TBC (7.32 log CFU/ml) than dairy farm milk samples (6.83 log CFU/ml) and pauperized milk samples (6.75 log CFU/ml). Similarly, household milk samples had significantly higher Coliform load compared to dairy farms and pasteurized milk samples. Total staphylococci counts (TSC) and YMC significantly vary between sources. Household milk samples had the highest TSC and YMC count while pasteurized milk samples had the least TSC and YMC count. Twelve bacterial genera were identified from each milk sample from all sources. However, the degree of occurrences of each genus varies between milk sources. While the isolation rate of Enterobacter, Escherchia, and Shigella species of raw milk samples from the households was significantly higher than in milk samples from dairy farms, the percentage of positive milk samples for Proteus species, coagulase negative Staphylococcus and coagulase postive Staphylococcus was higher in dairy farm milk samples than in milk sample from households. The present study has shown that the quality of milk produced in the area and the retail brands of pasteurized milk sold in various supermarkets in the area had poor microbiological quality and are unsafe for consumption. Hence, adequate sanitary measures should be taken at all stages from production to consumption to keep the safety of the consumers particularly children.