A Novel Approach Using a Protective Desiccant Increases Shelf Life and Reduces Moisture in Oil Suspensions of Freeze-Dried Limosilactobacillus reuteri

Abstract To ensure efficacy of probiotic products, it is essential that adequate numbers of bacteria survive during the intended shelf life, a quality factor that is greatly challenged by exposure to moisture. This study aimed to investigate if the shelf life of freeze-dried Limosilactobacillus reuteri strains formulated in oil could be prolonged using a moisture-absorbing technology. We show that by incorporating a desiccant strip in the oil suspension, we effectively control the moisture content until the end of shelf life and consequently increase survival of L. reuteri DSM 17938 and L. reuteri BG-R46 ® . This enables a shelf life of oil-formulated L. reuteri of more than 24 months at 25 °C. Batches lacking the desiccant strip had a dramatic reduction in viable bacterial counts, falling below the specified quality limit after only 6 months of storage at 25 °C. The loss of viable bacteria in batches without the desiccant strip was significantly higher than batches supported by the desiccant strip at all time points after 2 months ( p = 0.0025). There was a strong negative correlation between water content and CFU in batches lacking the desiccant strip, whereas no such correlation was observed in batches containing the desiccant strip. In conclusion, this paper demonstrates a novel method using a desiccant strip technology in probiotic oil suspensions (LongevityGuard ® ), which efficiently increases shelf life and protects freeze-dried probiotics from moisture-induced cell death and product spoilage. Graphical Abstract