This study was aimed to evaluate the nutritional quality and compare the general physic-chemical characteristics and microbial properties of camel milk in North Sinai Governorate. The samples were collected from camel grazed on open and close pastures. Also compare the concentration of some elements, amino and fatty acids of the milk samples for both systems. The biological and caloric values were evaluated in both systems. A section of this study was intended to study some technological properties such as coagulation time and curd tension. The analytical result indicated a wide variation between the major components of the samples for both gazing systems. There were high significant differences of some physical properties i.e. specific gravity, viscosity, flow index, consistency index and density and there was insignificant difference of freezing point of milk samples of close and open pasture (P< 0.0001). The average of titratable acidity and pH value were 0.175 %, 6.62 and 0.16 %, 6.66 of close and open system respectively. All elements content expect P show high significant differences between milk of close and open pastures (P< 0.0001). All minerals concentration except Fe were higher of camel milk of open than close system. Sum of amino and fatty acids, cholesterol, biological and caloric values were higher of open than those of close system. The results of technological properties indicated that coagulation time decreased when added the rennet to camel milk which incubated with yoghurt starter at 12-15 min., the range of curd tension was 28-42 g. All samples of open were higher of aerobic count, lactic acid bacteria and moulds & yeasts than those of close system, while coliform numbers was higher in the samples of close than that of open system samples. 60 % of the examined samples were positive for Staphylococcus of both systems. All samples were tested for pathogenic bacteria which were negative for Salmonella spp., Listeria and Escherichia coli 0157:H7.

The protolytic activity of 14 strains of Bacillus spp isolated from milk samples collected from different governorates in Egypt was evaluated . The strains were inoculated in pasteurized buffaloes milk incubated at 30 o C for 5 hours .Acidity, pH ., soluble nitrogen ( SN) and non protein nitrogen (NPN) as % of total nitrogen (TN) were determined during the incubation period . The tested strain showed a wide range of protolytic activity as indicated by the rate of soluble nitrogen ( SN) and non protein nitrogen (NPN) contents during incubation . The strain No 4,6 and 8 coagulated milk after 2 hours of incubation and showed the highest levels of both SN and NPN content . So these strains could be recommended the production of milk clotting enzyme .The inhibitory affect of Lactobacillus acidophilus , Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. casei on Bacillus were evaluated use by diffusion method on nutrient agar media for the fourteen Bacillus spp. It was found that the inhibtory of Lactobacillus acidophilus was more than Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. casei except on B . sphaercus . The inhibitory effects of L. acidophilus ; L. delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. casei was the same. Further mores the effect of heat treatment within the temperature range of 85-135 o C. , and various exposure times was studied . The highest resistance was found in case of B . amyloliquficans spores , which survived the temperature of 135 o C. the greatest reduction of spore numbers was found for B .cereus .

Viability of Lactobacillus acidophilus (L. acidophilus) and Bifidobacterium bifidum (B. bifidum) incorporated with yoghurt culture in three combinations of starter cultures; Treatment 1 (yoghurt culture + L. acidophilus), T2 (yoghurt culture + B. bifidum) and T3 (yoghurt culture + L. acidophilus + B. bifidum) were studied. Analyses of pH, titratable acidity (TA), syneresis, acetaldehyde content and sensory evaluation after 1, 3, 7, 14 and 21 days of cold storage of yoghurt were under taken. Counts of L. acidophilus was recorded 5.85 log 10 cfu g-1 in T1 which were higher than counts in T3 (5.79 log 10 cfu g-1) at the end of storage period. On the other hand, the viability of L. acidophilus and B. bifidum was stable until 14 days of storage period. The results showed that the addition of B. bifidum to yoghurt culture (T2) increased TA of bio-yoghurt comparing with addition of L. acidophilus (T1). Syneresis in all treatments was in the range of 20 to 33% and it was found higher in T3 than control. The highest sensory values were in control, T1 and T2 until the end of 14 days of storage period.