Shelf-life dynamics of key probiotic populations in dairy formulations: A temporal stability assessment

This paper aims to conduct a preliminary temporal evaluation of the stability of Lactobacillus and Bifidobacterium spp. throughout the designated shelf life of probiotic dairy products. The enumeration of viable probiotic bacteria was conducted during the first week and at the end of the shelf life in seventeen commercial probiotic products. In the initial analysis, fourteen products contained live bacterial populations exceeding the recommended threshold of 6 log CFU/mL or CFU/g. Twelve products retained probiotic levels above this threshold at the end of the shelf life. Lactobacillus spp. counts were above 6 log CFU/mL or CFU/g in 13 products during the first week. Although a reduction was observed in 10 products throughout storage, 11 products maintained sufficient Lactobacillus viability by the end of the shelf life, while two products showed complete loss. Regarding Bifidobacterium spp., eight products met the 6 log CFU/mL level at the beginning and end of the shelf life. In contrast, the population declined to undetectable levels in three products. Notably, Bifidobacterium spp. indicated on the label were not detected in four products during the first week, and this number increased to seven products by the end of shelf life. These findings underscore the variability in probiotic survival across different products and raise concerns about the consistency between product labelling and actual microbial content over time. The viability and stability of Lactobacillus and Bifidobacterium populations in probiotic dairy products are crucial for their health benefits. Understanding the factors that influence their survival and optimising processing and storage conditions is essential for improving product effectiveness. Ongoing research into novel preservation techniques will be key to ensuring the reliability of these probiotics in dairy products.