الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
A total of 80 random samples of fluid fermented milks, 40 samples of natural fermented milk (Laban rayeb) and 40 samples (20 each of pasteurized Laban rayeb and stirred yoghurt) were collected in their retail packages from different markets and dairy shops in Zagazig city and examined for sanitary and microbiological evaluation.
The obtained results indicated that the mean values of titratable acidity for examined natural fermented milk (laban rayeb) and pasteurized (laban rayeb and stirred yoghurt) were 1.37, 1.05 and 1.28%, respectively.
Furthermore, the obtained results indicated that the mean values of total coliform count in examined samples of natural fermented milk (laban rayeb) were 1.78x106/ml, but it can’t be detected in pasteurized (laban rayeb and stirred yoghurt).
The most prevalent coliform species isolated from examined natural fermented milk (laban rayeb) were, E.coli, Klebsiella pneumonaie, Klebsiella oxytoca and Enterobacter aerogenes at percentage of 41.2, 26.5, 20.6 and 11.7%, respectively.
On the other hand, the incidence of serologically identified E. coli as Enteropathogenic E. Coli (E coli O55:H7), Enterotoxogenic E. coli (E coli O128:H2 and, E coli O125:H21) and Enterheamorrhagic E. coli (E coli O26:H11 and E coli O111:H4).
PCR indicated that both (Stx1 and Stx2) were detected in serotypes (E. coli O26, O111 and O125), while Stx1 only was detected in serotype O128 and Stx2 only was detected in serotype O55.
Furthermore, the obtained results indicated that the mean values of total staphylococci count in examined samples of natural.