摘要 : One hundred random samples, fifty of natural yoghurt (plain) and 25 each of fruit yoghurt (strawberry) and flavored yoghurt (honey) were collected from different dairy shops and markets in Sharkia Governorate, Egypt. The collected... 展开 One hundred random samples, fifty of natural yoghurt (plain) and 25 each of fruit yoghurt (strawberry) and flavored yoghurt (honey) were collected from different dairy shops and markets in Sharkia Governorate, Egypt. The collected samples were examined physically (sensory evaluation), sanitary (determination of titratable acidity), and bacteriologically. The obtained results revealed that the highest frequency distribution of examined yoghurt samples based on suggested score for sensory evaluation was 44% of examined natural yoghurt samples and lies within the range of 93-100%, while 72% of the examined fruit yoghurt samples and 88% of examined flavored yoghurt lie within the same range. Acidity% in natural and fruit yoghurt samples was 0.83% and 0.90%, respectively, while in case of flavored yoghurt samples was 1.06%. The mean coliform count/g in examined yoghurt samples was 4.6x10⁴ and 4.7x10³ for natural and fruit yoghurt, respectively while, coliform organisms in examined flavored yoghurt were 4.6x10²/g. The most prevalent coliform species isolated from examined natural and fruit yoghurt samples were <i>Citrobacter freundii</i>, <i>Enterobacter agglomerans</i> and <i>K. oxytoca</i> in percentages of (20%, 14% and 18%) and (12%, 16% and 8%), respectively, while in the examined flavored yoghurt samples the most prevalent coliform species were <i>Citrobacter freundii</i> and <i>Enterobacter agglomerans</i> in percentages of 8% and 4%, respectively. The mean staphylococci count/g in examined natural and fruit yoghurt was 1.7x10⁴ and 5.2x10², respectively but in case of flavored yoghurt it was 1.6x10³. <i>Staphylococcus aureus</i> and <i>Staph. epidermidis</i> were the predominated staphylococci isolated from the examined natural, fruit and flavored yoghurt samples in percentages of (12% and 6%), (12% and 4%) and (4% and 4%), respectively. <i>Salmonellae</i> failed to be detected in examined samples. Yersinia spp. could be detected in 16% out of examined fruit yoghurt samples while they couldn't be detected in both examined natural and flavored yoghurt samples. <i>Yersinia pseudotuberculosis</i>, <i>Y. intermedia</i> and <i>Y. kristensenii</i> could be isolated from the fruit yoghurt samples in percentages of 8%, 4% and 4%, respectively. The sanitary and public health importance of isolated microorganisms as well as their control measures were discussed to improve the quality of yoghurt and to safe guard the consumers from infection. 收起