Chemical and Bacteriological Assessment of Raw Milk Collected from Some Dairy Farms in El-Behera Governorate, Egypt.

Abstract

Milk is an essential food for humans and is considered as a good medium for microbial growth. Therefore, 120 raw milk samples from some dairy farms were obtained for bacteriological and chemical evaluation. Chemical evaluation of the examined raw cow’s milk samples showed mean values of fat, protein, casein, solid not fat, lactose, galactose, glucose, urea contents were (4.25±0.11), (3.06±0.06), (2.27±0.03), (8.38±0.10), (4.51±0.04), (0.29±0.06), (0.72±0.08), and ( 27.90±1.45), respectively. The determination of acidity of examined samples showed that the mean values of acidity degree, lactic acid and citric acid were (19.85±1.22), (0.19±0.01), and (0.12±0.01), respectively. The freezing point was (-0.46±0.01). Moreover, Mean values of aerobic plate count, coliform count and Staphylococcus aureus count were (2.9x105±0.16x105), ( 3. 8x103±0.13x103), and (3.1x103 ± 0.12x103), respectively .Escherichia coli prevalence was20%(24/120), while the prevalence of Mycobacterium bovis was 3.33% (4/120). E. coli isolates were serogrouped into O111, O26, O91, O44, O128, and untyped serogroups. The molecular characterization of five E.coli isolates revealed that; all tested strains showed ompA gene and only two showed stx1 gene. While resistance genes (bla TEM and aac(3)-IV) were detected in all tested strains. All tested S. aureus isolates showed virulence genes (Spa gene and PVL gene) and resistance genes (mecA and aac gene). Antibiotic sensitivity testing revealed the presence of multidrug resistant (MDR) isolates. The public health importance of isolated microorganisms was discussed