الفهرس 
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Abstract
One handred and fifty samples (fifty each of fresh raw cream, yoghurt and Damietta cheese) collected from markets and shops in different localities in Zagazig city, were subjected for sanitary and microbiological examination.
The mean acidity percentage in examined cream samples was 0.18 + 0.005, and in yoghurt was 0.944 + 0.033 while it was 0.744 + 0.044 in Damietta cheese.
The mean total colony count in examined samples of cream, yoghurt and Damietta cheese were 1.166 x 103 + 0.168 x 103/ml., 1.199 x 1011 + 0.215 x 1011/g. and 6.499x107 + 1.166 x 107/g. respectively.
Coliform organisms could be detected in all samples of raw cream samples and in 74% and 60% of yoghurt and Damietta cheese samples respectively. The mean coliform counts (MPN/100 ml.(g.) were 1.215 x 1013 + 0.263 x 1013, 6.75 x 109 + 2.593 x 109 and 5.02 x 102 + 0.8 .1 x 102 in examined samples respectively.
Examined samples of cream, yoghurt and Damietta cheese proved to be contaminated with E. coli at percentages of 10%, 16% and 2% respectively.
Enterobacter aerogenes, E. liquefaciens, E. hafinae, E. cloacae, Klebsiella and Citrobacter. spp. could be isolated from examined cream, Yoghurt and Damietta cheese samples at varing percentages ranging from 2 % - to 36 %.
Serological-typing of isolated E. coli strains revealed identifica-
tion of serotypes : 0 : K , 0 : K and 0 : K .
127 63 26 60 126 71 Salmonella and shigella organisms failed detection in all
examined samples, while Proteus vulgaris and Proteus merabilis could be isolated from 10% and 4% of cream samples. P. rettegri could be isolated from 2%, 4% and 6% of raw cream, yoghurt and Damietta cheese respectively; while P. morganii was detected in 4% and 18% of yoghurt and Damietta cheese samples respectively.
The mean total enterococci counts/m1.(g.) of cream, yoghurt and Damietta cheese were 5.659 x 105 + 1.656 x 105, 6.425x103+ 1.466 x 103 and 2.025 x 103 + 0.319 x 103 respectively.
Strept. faecalis was present in 68% , 40% and 40% of cream, yoghurt and Damietta cheese respectively, while Strept. faecium and Strept. intermediate were present in examined cream and yoghurt samples at varying percentages ranging from 8% to 28%. Staphylococci were present in 52%, 34% and 4% of cream, Yoghurt and Damietta cheese samples with a mean counts of 5.22x105 + 1.65 x 105, 3.41 x 103+ 0.82 x 103 and 4x102+0.89x102 respectively. Coagulase positive staphylococci proved to exist in 24%, 4% and 4% of examined cream, yoghurt and Damietta cheese samples respectively. The relationship between coagulase and DNAase test was recorded. The public health importance of isolated organism as well as suggested measures for improving the products were discussed.