Safety features of lactobacilli from bryndza cheese and whey inferred from whole genome sequencing

Lactobacillaceae are candidates for starter or adjunct cultures for the production of bryndza cheese with traditional organoleptic properties, in particular well adapted strains isolated from bryndza cheese or from ewes' whey. Whole genome sequencing of 34 such strains was carried out, their taxonomic classification was done and the genomes were analysed for the presence of genes responsible for antibiotic resistance or production of biogenic amines. Taxonomic classification of the strains was achieved using several bioinformatic tools, with most weight assigned to Type Genome Server (TYGS). Based on this, qualified presumption of safety (QPS) status as defined by European Food Safety Authority could be assigned to 25 strains, which belonged to species Lacticaseibacillus paracasei/casei, Limosilactobacillus fermentum, Lactobacillus helveticus, Lactiplantibacillus plantarum and Leuconostoc lactis. None of the strains was found to harbour in the genome any acquired antimicrobial resistance genes to clinically relevant antimicrobials. None of the strains contained genes conferring production of the two most hazardous biogenic amines, histamine and tyramine. All strains were predicted to be non-pathogenic for humans by PathogenFinder (Technical University of Denmark, Copenhagen, Denmark). Based on the results, 25 out of 34 tested strains fulfilled safety requirements for the development of starter or adjunct cultures for the production of bryndza cheese with traditional organoleptic properties.