Effects of conventional and nonconventional drying on the stability of Bifidobacterium animalis subsp. lactis INL1

Abstract

Freeze, spray, vacuum, microwave vacuum- and microwave freeze-drying were applied to Bifidobacterium animalis subsp. lactis INL1. Freeze and microwave freeze-drying showed the highest survival after drying. When a storage test (25 °C; oxygen) was performed, these cultures were the most sensitive ones at aw = 0.23, but the addition of lactose improved their stability after 8 weeks. Flow cytometry was useful to assess viability after drying but not during storage. Our results show that dehydration technologies other than freeze-drying might be suitable alternatives that deserve further investigation for the preservation of sensitive probiotic bacteria. Microwave drying rendered cultures of comparable characteristics to their conventional counterparts, requiring significantly shorter drying times.