A study was carried out on the plain yoghurt was prepared on laboratory in a scale production from cow's milk obtained from dairy farm in Cairo. Plain yoghurt blended with fresh juice (Guava, Mango, Strawberry juice) and commercical yoghurt fortified by juice have been investigated. The microbiological quality of yoghurt, yoghurt juice blends and fresh juice samples were investigated during refrigerated storage at 40C for two weeks, and six months for juice kept frozen. The microbial analyses including Yeast and moulds counts, and coliform organisms were recorded statistically evaluated. The result of the study showed that fresh juice had significant effect on acceptability of yoghurt before and after storage.