الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
A total of 105 Kareish cheese samples were collected from New Valley, Cairo markets and factory-manufactured products (35 of each) which were subjected to sensory examination (color, odor and consistency), chemical examination (pH and Salinity) and microbiological examination (counts of Coliforms, E. coli, S. aureus and isolation of Salmonella spp. and L. monocytogenes and mold and yeast c
All the collected samples were sensory accepted. Regarding salinity, samples form New Valley were significantly (P<0.05) the highest mean values (3.9±0.83) then factories’ samples (2.2±0.16), then Cairo markets samples (1.3±0.39). The mean pH values from different sources didn’t significantly (P>0.05) differ from each other ranging from 4.2±0.06 to 4.6±0.05.
For coliforms count, 43% (45) of the total samples were more than ES limit; 49% (17) of each of Cairo and factories samples and 31% (11) of New Valley samples. There was no significance difference (P>0.05) between mean coliforms count from different sources with total mean ± SE of 3.45 ± 0.22 log cfu/g.
Regarding mold and yeast counts, 100% (35), 94% (33) and 74% (26) were positive to the count in New Valley, Cairo and Factories samples, respectively with 90% (94) of the total collected samples with mean ± SE count of 4.62 ± 0.13 log cfu/g. There was no significant difference (P>0.05) between the mean counts in samples from New Valley (4.85±0.07) and Cairo sample (4.84±0.21), meanwhile the mean count of factories samples (3.75±0.45) was significantly (P<0.05) lower than both of them.
E. coli count was found in 30% (32) of total samples with mean ± SE of 1.92 ± 0.22 log cfu/g. The incidences were 17% (6) 29% (10) and 46% (16), in factories samples, New Valley and Cairo markets, respectively.
None of S. aureus, Salmonella spp. or Listeria monocytogenes was detected in any of the examined kariesh cheese samples collected from different localities.
The experiment was designed to explore the effect of lemon juice and vinegar on survival of E. coli and S. aureus during manufacturing of Kareish cheese using each of them as an alternative method for traditional manufacturing method. Both treatments didn’t alter the traditional flavor of Kariesh cheese.
The results indicated that vinegar has effective role in control of E. coli contamination during manufacturing of kariesh cheese, and this effect is more significant if cheese was stored in its whey, with reduction in the count by about 3 logs than cheese stored without whey and more than 4 logs than the control. On the contrary, treatment with lemon juice has no effect on E. coli contamination or growth control.
The count of S. aureus in kariesh cheese prepared with vinegar and stored in whey, was significantly (P<0.05) lower than the count in other treatments, with reduction of 3.6 logs. On the other hand, S. aureus counts in kariesh cheese made by lemon juice were reduced by 1.1 log in cheese stored without whey and 1.5 log in cheese stored in whey than the control
On the other hand, the lowest reduction in S. aureus count (about 0.3 log) was recorded in kariesh cheese prepared using vinegar and stored without its whey which reached to 6.8±0.1 log cfu/g by the 15th day of storage.
The results indicated that best control of E. coli and S. aureus contamination in kariesh cheese is the treatment of milk with vinegar and storage of cheese in its whey. It would be an effective alternative for traditional manufacturing of kariesh cheese to reduce counts but not prevent public health hazards completely