Prevalence of Enterococci and Streptococci in Raw Milk and Some Dairy Products and The Subsequent Alteration on Quality

Document Type : Scientific and Research

Authors

1 Animal Health Research Institute

2 Animal Health Research Institute, Damanhour branch

3 Alexandria branch AHRI, Egypt

Abstract

The purpose of this research was to study the prevalence of enterococci and streptococci in milk and some dairy products. Survey included 50 samples of raw milk, 25 kareish cheese and 25 yoghurt samples which were collected from El-Behera governorate markets. The results revealed that the mean of chemical composition was 12.95±0.11, 86.34±0.26, 6.3±0.07 and 0.18±0.002 for total solid, Moisture content, pH values and titratable acidity, respectively. in raw milk samples; 36.8±0.87, 61.76±0.84, 3.87±0.11 and 2.27±0.037 in kareish cheese and 36.8±0.87, 76.48±0.94, 4.33±0.05 and 1.09±0.036 in yoghurt samples, Respectively. incidence of positive samples for aerobic plate count, streptococci and enterococci count were 88 , 26 and 22 % in raw milk samples, respectively . 76 , 36 and 36 % in kareish cheese and 56, 28 and 32 % in yoghurt samples, respectively. with mean values of 1.22x105 ±0.1x105, 4.5x103 ±0.7x103 and 6.3x103 ±1.9x103 cfu/ml in raw milk samples; 8.9x104 ±0.76x104 , 4.7x103 ±0.87x103  and 5.7x103 ±1.6x103 cfu/gm in kareish cheese samples and in yoghurt samples were 7.6x104 ±0.59x104 , 3.7x103 ±0.6x103 and 5.5x103 ±0.64x103 , respectively. All isolated Enterococcus faecium, Enterococcus faecalis, S. agalactiae and S. dysgalatiae were confirmed at a genus level using specific primer targeting 16s rRNA gene in S. dysgalatiae and Enter. Faecalis; sod A gene in enterococcus faecium and cfb gene in S. agalactiae. Desired amplicon for virulence genes were obtained.

Keywords

Main Subjects