الفهرس 
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Abstract
Two hundred from different dairy products samples (Kareish cheese, Damietta cheese, plain yogurt and ice cream) were collected randomly from supermarkets, small dairies and street-vendors at Alexandria City, Egypt. (50 of each) The samples obtained as sold to the public and transferred with a minimum delay to the laboratory to be examined.
The results can be summarized as follows:
7.1. Prevalence of Escherichia coli and Verotoxigenic Escherichia coli in examined locally manufactured dairy products samples.
• The prevalence of Escherichia coli in examined locally manufactured dairy products samples using was EMB agar 76% (19/25), 0% (0/25), 20% (5/25), 60% (15/25), 24% (6/25), 44% (11/25) and 0% (0/50), positive samples from street-vendor and supermarket Kareish cheese, street-vendor and supermarket Damietta cheese, Supermarket Plain yogurt and Small dairies plain yogurt, and Street-vended Ice cream, respectively.
• The respective prevalence of E.Coli on Sorbitol MacConky agar give rise to 24% (6/25), 0% (0/25), 8% (2/25), 16% (4/25), 12% (3/25), 12% (3/25) and 0% (0/50) while, Indole test result revealed that 73.33% (15/25), 0% (0/25), 0% (0/25), 52% (13/25), 12% (3/25), 48% (12/25) and 0% (0/50) were positive samples from street-vendor and supermarket Kareish cheese, street-vendor and supermarket Damietta cheese, Supermarket Plain yogurt and Small dairies Plain yogurt and Street-vended Ice cream, respectively.
• Only 8% (2/25) positive samples from street-vendor Kareish cheese and the rest of samples are complied with Egyptian stendards.
• Serodaignosis of E.coli isolated from examined locally manufactured street-vendor Kareish cheese O26 (8%), O55 (4%) , O127 (4% ) while 8% of isolate were untypable but in street-vendor and supermarket Damietta cheese samples E.coli could be identified serlogically into O86a (8%), O127 (12%) and 4% untpable while, in supermarket plain yogurt and small dairies Plain yogurt O55(8%) and O86a (16% ) could be identified.
• Verotoxigenic Escherichia coli could be detected only in 8% (2/25) in examined street- vendor Kareish cheese while failed to be detected in supermarket plain yoghurt, and small diaries plain yoghurt based on molecular identification. It revealed that that only 8% (2/25) positive samples from street-vendor Kareish cheese and the rest of samples are complied with Egyptian stendards ES: 1008-4/2005.
• The screening for E. coli determinant gene (phoA) and virulence genes (stx1, stx2, eaeA) showed that all screened E.coli strains had a determinant gene (phoA) while, stx1 and stx2 genes could be detected only in of selected street-vended Kareish cheese isolates., meanwhile both virulence genes could not be detected in all selected small dairies plain yoghurt isolates. On contrary, virulence gene eaeA could be detected in all test E.Coli isolates from street-vendor Kareish cheese and small dairies plain yoghurt.
7.2. Prevalence of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) in examined locally manufactured dairy products samples
• Identification of coagulase-positive staphylococci using cultural agar media give rise to 88% (22/25), 48% (12/25), 84% (21/25), 88% (22/25), 52% (13/25), 60% (15/25) and 36% (18/50) isolated from street-vendor and supermarket Kareish cheese, street- vendor and supermarket Damietta cheese, supermarket Plain yogurt and small dairies Plain yogurt and Street-vended Ice cream samples, respectively.
• By Conventional identification coagulase test , it pointed out that Staphylococcus aureus could be isolated by 12% (3/25), 4% (1/25), 20% (5/25), 32% (8/25), 8% (2/25), 32% (8/25) and 0% (0/50) from street-vendor and supermarket Kareish cheese, street-vendor and supermarket Damietta cheese, Supermarket Plain yogurt and small dairies Plain yogurt and Street-vended Ice cream samples, respectively.
• Staphylococcus aureus could not be detected in ice cream products samples, therefore all examined samples were complied with Egyptian Standards (Egyptian Organization for Standardization and Quality Control [EOSQC] 2005a, b, c, d, e) for ice cream ES:
1648/2005 which stated that these products should be free from all pathogenic microorganisms and their toxins.
• All examined pooled locally manufactured dairy products samples are free from Staphylococcal enterotoxins by using sandwich ELISA qualitatively (A,B,C,D and E) Enterotoxins.
• The screening for coagulase-positive Staphylococcus aureus determinant gene (23S rRNA) in presumptive coagulase-positive isolated from examined locally manufactured dairy products samples by Molecular identification PCR revealed that all selected isolates were proved to carry determinant gene (23S rRNA) by 12% (3/25), 4% (1/25), 20% (5/25), 32% (8/25), 8% (2/25), 32% (8/25) from street-vendor and supermarket Kareish cheese, street-vendor and supermarket Damietta cheese, Supermarket Plain yogurt and small dairies Plain yogurt samples, respectively for determinant gene (23S rRNA).
• The screening for methicillin-resistant Staphylococcus aureus gene (mecA) in presumptive coagulase-positive isolated from examined locally manufactured dairy products samples by Molecular identification PCR revealed that all selected isolates were proved to carry 12% (3/25), 4% (1/25), 4% (1/25), 0% (8/25), 0% (8/25) and 4% (1/25) from street-vendor and supermarket Kareish cheese, street-vendor and supermarket Damietta cheese, Supermarket Plain yogurt and Small dairies Plain yogurt respectively for methicillin-resistant Staphylococcus aureus (MRSA) gene mecA gene.
7.3. Prevalence of foodborne pathogens in examined kareish cheese samples .
• The result given revealed that 8% (2/25) of examined street-vendor Kareish cheese is contaminated by VTEC and the 16% (4/25) of examined street-vendor and supermarket Kareish cheese is contained MRSA.
7.4. Prevalence of foodborne pathogens in examined Damietta cheese samples.
• All examined Damietta cheese samples were proved to be free from VTEC and only
4% (1/25) of examined Damietta cheese samples was contaminated by MRSA.
7.5. Prevalence of foodborne pathogens in examined yoghurt samples
• All examined yoghurt samples were proved to be free from VTEC and only 4% (1/25) of examined yoghurt samples was contaminated by MRSA.
7.6. Genes sequencing and phylogenetic tree
• The PCR products of E.Coli different genes were studied for sequencing. The sequences were accepted and received accession numbers from GenBank are (MW276033), (MW276034), (MW276038), (MW311073) .
• The results of nucleotide sequencing of S.aureus were accepted and received accession numbers from Gen Bank are (MW25675), (MW25675), (MW256758), (MW256759(,)MW256760) and (MW256761).