Abstract
Contamination of raw milk by different types of microorganisms from different sources would constitute a public health hazard. Therefore, this study aimed to assess chemical, sanitary and microbiological quality of raw cow bulk milk collected from different sources (dairy farms, collecting & distributing centers and dairy shops & supermarkets), 50 samples from each source. The obtained results revealed that gross chemical composition of raw bulk milk from dairy farms and collecting center nearly similar but low values was noticed in bulk milk collected from dairy shops and supermarket, bulk milk collected from collecting centers have higher values of pH and acidity than other source. All bulk milk samples from different source were contaminated with total bacterial count with different levels, while Staph. aureus and total Enterobacteriaceae were detected in (4,4, 8%)and (4, 8, 10%) of examined raw bulk milk collected from dairy farm, collecting & distributing centers, and dairy shops & supermarkets, respectively. The most prevalent enterobacteriaceae species isolated from raw bulk milk from different sources where was Citrobacter freundii 22% followed by Klebsiella pneumonia 18% while the most prevalent mould species isolated from raw bulk milk were penicillium spp. and Aspergillus niger (14% for both) while Rhodotorula species (14%) followed by candida tropicalis (10%)were the most prevalent yeast species isolated from bulk milk collected from different sources.In conclusion, higher incidence of indicator microorganisms was noticed in raw bulk milk collected from dairy shops and supermarkets would lead to a public health hazard and/or economic losses due to spoilage of raw milk, therefore, strict hygienic conditions are required during the production cycle from producer to consumers.

Key words: Bulk milk, Staph. aureus, enterobacteriaceae, yeast, mould.