There was a significant difference in pH between plain yogurt and all of the stirred fruit yogurts at the end of the shelf life. This pH decline may have been due to continued fermentation by the lactic acid bacteria and the contribution of the acidity of the added fruit juice. Yogurts in this study were produced using a culture containing both S. thermophilus and L. delbrueckii spp bulgaricus which accelerate post fermentation acidification in yogurt during storage compared to starter cultures which are devoid of L. delbrueckii spp bulgaricus ( Kailasapathy et al., 2008). There were some statistically significant differences in the mean levels of acidity among the plain and fruit yogurts one week after production, however, it is highly unlikely that these differences have any real practical significance.