Assessment of the quality of conventional yogurt as affected by storage

The study was conducted to determine the changes in nutritive value and microbiological quality of fresh yogurt and that stored under household conditions. Samples of yogurt were collected from different shops and households at Faisalabad. The quality of conventional yogurt was assessed by chemical analysis and microbial count. The consumer's acceptability of fresh yogurt was assessed organoleptically. The nutritive value of yogurt was determined by acidity, pH, moisture, protein, ash and syneresis. The microbiological examination included viable count, fungal and E.coli contamination. The nutritional quality of freshly prepared yogurt whether drawn from shops or taken from households was similar except for moisture and syneresis which were higher in household yogurt than that of shops. During storage the percentage of acidity and protein increased in household yogurts but decreased in shop yogurt. However, the pH, moisture and syneresis of yogurt samples whether drawn from shops or from households increased, whereas ash percentage decreased during storage. The viable bacterial count in household yogurt increased during storage but decreased in shop yogurt and the number of E.coli also increased in conventional yogurt during storage. The fungi were detected only in fresh samples of the household yogurt but in shop yogurt they were also detected during storage. The organoleptic quality of freshly