Abstract
Milk is a nutritionally rich and biologically complex liquid, comprising fats, sugars, proteins, essential minerals, vitamins, and various bioactive components that contribute to human health. Both its precise chemical composition and microbiological quality dictate whether it is safe and suitable for human consumption and industrial processing applications. This comprehensive study assessed multiple physicochemical properties and microbial contamination levels of raw cow milk samples systematically obtained from diverse sources across Cairo and Delta regions in Egypt, including small-scale farms, informal street vendors, milk collection centers, local markets, and hypermarkets. A total of 159 representative samples were carefully analyzed over a six-month period for key physical properties (including pH, electrical conductivity, freezing point, and density), detailed chemical composition (fat content, protein percentage, lactose levels, ash, and solids-not-fat), and comprehensive microbial contamination profiles (aerobic mesophilic count, psychrotrophic bacteria, Staphylococcus aureus, Coliforms, enterococci, yeast, and mold populations). Microbial analysis revealed a significant contamination level, particularly with pathogenic Staphylococcus aureus (6.28–6.32 log CFU/mL), exceeding the Egyptian food safety standard limit of 2 log CFU/mL. Yeast and mold count also demonstrated concerningly elevated levels (5.01–5.48 log CFU/mL) across most samples. There is a significant difference (P<0.05) between raw milk collected from Cairo and Delta regions; Delta region samples consistently exhibited higher psychrotrophic bacterial counts (6.76 vs. 6.38 log CFU/mL), while Cairo samples showed markedly higher enterococcal counts (6.21 vs. 5.28 log CFU/mL). While the physicochemical properties of the milk samples generally met the Egyptian standard quality requirements, the widespread microbial contamination poses a serious and direct public health hazards. These critical findings reveal the need for substantially improved hygiene practices during all stages of milk production including milking procedures, handling samples, and storage conditions to ensure ultimate consumer safety and product quality.

Key words: Raw milk quality, microbial contamination, food safety, Egypt, public health, regulatory compliance.