Abstract
Contamination of milk by different types of microorganism from different sources would constitute a public health hazard. Therefore, this study aimed to assess chemical composition, sanitary and microbiological quality of raw bulk milk collected from different sources (dairy farms, collecting & distributing centers and dairy shops & supermarkets), as well as 50 samples from each source. The obtained results revealed that gross chemical composition of bulk from different sources nearly similar but low values was noticed in bulk milk collected from dairy shops and supermarket. Regarding to pH and acidity, bulk milk collected from collecting centers have high values in addition, 16% of bulk milk collected from dairy supermarket were positive for alcohol precipitation test. Concerning microbiological evaluation, all bulk milk samples were contaminated with total bacterial count with different levels, Staph. aureus count, total coliforms, and total Enterobacteriaceae were detected in (4, 4, 8%), (4, 6, 8%) and (4, 8, 10%) of examined bulk milk collected from dairy farm, collecting & distributing centers, and dairy shops & supermarkets, respectively. The most prevalent mould species isolated from bulk milk were penicillium and Asp. Niger (14% for both) while Rhodotorula (14%) followed by candida tropicalis (10%) were the most prevalent yeast species isolated from bulk milk collected from different source. In conclusion, higher incidence of indicator microorganisms was noticed in 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: Key words: Bulk milk, Staph. aureus, Coliforms, Enterobacteriaceae, yeast, mould.