Genetic Diversity of Leuconostoc mesenteroides Isolates from Traditional Montenegrin Brine Cheese

In many dairy products, Leuconostoc spp. is a natural part of non-starter lactic acid bacteria (NSLAB) accounting for flavor development. However, data on the genomic diversity of Leuconostoc spp. isolates obtained from cheese are still scarce. The focus of this study was the genomic characterization of Leuconostoc spp. obtained from different traditional Montenegrin brine cheeses with the aim to explore their diversity and provide genetic information as a basis for the selection of strains for future cheese production. In 2019, sixteen Leuconostoc spp. isolates were obtained from white brine cheeses from nine different producers located in three municipalities in the northern region of Montenegro. All isolates were identified as Ln. mesenteroides. Classical multilocus sequence tying (MLST) and core genome (cg) MLST revealed a high diversity of the Montenegrin Ln. mesenteroides cheese isolates. All isolates carried genes of the bacteriocin biosynthetic gene clusters, eight out of 16 strains carried the citCDEFG operon, 14 carried butA, and all 16 isolates carried alsS and ilv, genes involved in forming important aromas and flavor compounds. Safety evaluation indicated that isolates carried no pathogenic factors and no virulence factors. In conclusion, Ln. mesenteroides isolates from Montenegrin traditional cheeses displayed a high genetic diversity and were unrelated to strains deposited in GenBank.