Sour milk, or "set yogurt" as defined by European terminology, is the most popular fermented dairy product in the region and has enjoyed growing global popularity over time. Access to international markets requires effective product protection, which can be achieved through the use of bioprotective probiotic cultures. This study aimed to investigate whether the addition of bioprotective cultures induces any changes in the qualitative properties of set yogurt initially inoculated with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The research material consisted of set yogurt samples supplemented with three different bioprotective cultures, along with a reference control. The study evaluated pH, fatty acid profiles, microbiological analyses and sensory characteristics, assessed by two independent sensory panels. The sensory attributes analyzed included appearance, aroma, consistency, spoon consistency, mouthfeel, taste/acidity, and aftertaste. Statistical analysis of the results demonstrated that the addition of bioprotective cultures did not significantly affect the qualitative properties of set yogurt during storage period.