Safety assessment and fermentation potential of Lactiplantibacillus plantarum L3 isolated from the traditional Chinese fermented food Bianba for yogurt production

Bianba is a Chinese fermented food with a long history, whereas the microorganisms involved in its fermentation remain poorly understood. Currently, a strain of Lactiplantibacillus plantarum was isolated from Bianba and named L3. Genomic analysis emphasized the functional annotation of protein-coding genes in L3 specifically for carbohydrate utilization. Risk sequences (antibiotic resistance and virulence genes) were detected, and L3 was deemed safe based on the outcomes of tests for antibiotic resistance, hemolysis, and gelatinase production. The L3 strain shows promise as an ideal culture for initiating yogurt fermentation due to its robust acid production and high tolerances to acid, bile salts, and gastric acids. Compared with the commercial starter fermented yogurt, the yogurt produced by L3 (L3Y) had a lower pH value, viscosity, and hardness, higher acidity, syneresis, and gumminess. Notably, the L3 cells in L3Y remained viable at levels greater than 10 log CFU/g even after being stored at 4 °C for 21 d without a significant decrease, and L3Y showed higher concentrations of important volatile flavor compounds, such as acetoin and diacetyl. Our results showed L3 carried safety characteristics and good potential to be applied in yogurt, which would be of interest to the dairy industry.