Cheese whey for production of breast milk-derived bifidobacteria: Influence of fermentation conditions on the survival to spray drying and storage

Common factors influencing the survival of microbes to spray drying include microbial intrinsic resistance, properties of the carrier, inlet and outlet temperatures, and rate of feeding. In this work, cheese whey was used as both a growth medium and a carrier for spray drying of Bifidobacterium animalis subsp. lactis INL1. The growth of the strain was favoured by acid conditions, reaching higher counts when pH was not controlled during fermentation and when pH was controlled at a constant value of 5.5, compared with 6.5. Powders containing ca. 9 log order (cfu/g) of B. lactis INL1 were obtained by direct spray drying of the culture coming out of the fermenter. No differences in survival to spray drying were observed in terms of fermentation conditions. However, fermentation conditions are considered to have influenced the strain's survival along the storage. Spray drying in acid conditions was detrimental to the survival along storage.