Determination of microbial contamination in raw milk, processed milk and yoghurt consumed in Mbarara city, western part of Uganda

Abstract

he microbial composition of milk serves as a key indicator of its quality. While its nutritional value is significant, the inherent nature of milk also makes it an ideal environment for the proliferation of microorganisms, some of which lead to human illnesses, while others contribute to the spoilage of milk, making it unsafe for consumption. This research therefore aimed to assess the bacterial contamination content in raw milk, UHT and yoghurt, a total of 36 samples were gathered from various retailers, markets and supermarkets across Mbarara city. Contaminated milk and its products are accountable for human dairy related illnesses. This cross-sectional study was conducted to assess micro bacterial contamination and the presence of selected milk-borne zoonotic pathogens. The study involved 36 samples of milk and milk products mainly raw milk, UHT, or processed milk and yoghurt. Laboratory analysis conducted included Total Plate Count (TPC), Yeasts and molds (YM), staphylococcus, salmonella and coliform, as well as detection of Escherichia coli (E coli), biochemical tests including gram staining were employed to isolate and identify bacteria in these samples. The findings indicated the presence of these types of bacteria in raw milk, Staphylococcus spp (25%), Salmonella spp (33.3%), YM (41.6%), TPC (50%), coliforms (33.3%) and E.coli (25%), for UHT milk the percentage was Staphylococcus spp (0%), Salmonella spp (16.6%), YM (8.3%), TPC(16.6%), coliforms (16.6%) and E.coli (8.3%), finally for yoghurt the results were Staphylococcus spp (8.3%), Salmonella spp (8.3%), YM (16.6%), TPC (25%), coliforms (16.6%) and E.coli (0%). In conclusion, the detection of microbial contamination in raw milk and milk products suggests inadequate sanitary practices and poor storage practices. Products that are contaminated by these pathogenic organisms when consumed may result in food poisoning and a proper awareness among the stakeholders and consumers regarding possible outcomes of consuming contaminated food items is necessary. keywords: Milk, Yoghurt, Food poisoning, Microorganisms, Contamination