A study of product stability of commercial probiotic fermented milk and yoghurt
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- Master's theses (KBM) 
In this study, the stability of three probiotic fermented milk products (‘Cultura Naturell’, ‘Biola Syrnet Lettmelk Naturell’ and ‘Biola Pluss Yoghurt Mild Naturell’) produced by TINE BA was studied and samples from each production were studied at three different times within designated shelf-life. The study focused mainly on the viability of probiotic bacteria during storage, which is a key criterion for quality evaluation of probiotic dairy products. Other parameters (pH, viscosity, organic acids, carbohydrates, volatile compounds and sensory attributes) were also measured for a comprehensive quality evaluation of these products. The three TINE probiotic fermented milk products studied are produced with different combinations of bacteria strains, raw materials and chemical ingredients and have shown different properties regarding to viable cell counts of bacteria, pH, viscosity, organic acids, carbohydrates, and volatile compounds. These variations determine their unique sensory characteristics and effect on customer’s decision upon purchase of the fermented milk products. In additional, variations between the three different productions of the same product were observed concerning pH, viscosity, organic acids, carbohydrates and volatile compounds, which however seem not to affect the sensory perception of these products in large extent . The viable cell counts of probiotic bacteria in TINE probiotic fermented milk product were satisfactory, maintaining above a level of 7 log cfu/g during storage at 4°C within designated shelf-life. This indicates that potential healthy beneficial could be obtained by regular consumption of TINE probiotic fermented milk products.