EFFECTS OF SODIUM BENZOATE ON PHYSICOCHEMICAL AND MICROBIOLOGICAL QUALITIES OF YOGHURT IN KANO METROPOLIS

The study was conducted to determine the physicochemical and microbiological quality of yoghurt prepared from raw milk preserved with sodium benzoate at varying levels and stored for 7 days under ambient temperature. The experiment was laid in a completely randomized design. The result of physicochemical analysis shows that the pH, protein, moisture, lactose, total solids, fat, solids- not -fat and ash were significantly (p<0.05) different across all the treatment during the storage period. In addition, the result also shows that the pH, moisture and protein values decrease with increase in storage period in yoghurt. While total solids, ash, titratable acidity, lactose, solids-not-fat and density increased indicating addition of sodium benzoate in the yoghurt and reduce rate of deterioration and enhances its shelf life. The Aerobic Mesophilic Mean Bacterial Count of yoghurt prepared using milk preserved with sodium benzoate at 0, 150, 200 and 250mg/l respectively indicate that there is decrease in number of aerobic mesophilic mean bacterial with increase in sodium benzoate at day 1. Furthermore mean value of 2.61×10-6 to 4.0×10-6cfu/ml was also recorded across the treatments at day 3, showing that presence of sodium benzoate reduces microbial count. Furthermore, only treatment 1 recorded value of 5.26×10-7 cfu/ml at day 7 which is an increased in microbial count indicating absent of sodium benzoate. No pathogenic microbes were detected. It is recommended that addition of sodium benzoate to yoghurt enhances the shelf life of the products as well as reducing the bacterial count at ambient temperature.