Resumen de In-depth analysis of the austrian cheese microbiome reveals high taxonomic and functional interactionswith the production facility environment
Alejandro Alcañiz, Rocío Olmo López, Franz Ferdinand Roch, Monika Dzieciol, Viktoria Neubauer, António Lourenço, Francesco Rubino, Evelyne Selberherr, Martin Wagner, Narciso Quijada
Vorarlberger Bergkäse (VB) is a hard-washed-rind cheese produced from raw milk of alpine cows in western Austria with Protected-Designation-of-Origin, without the addition of ripeningcultures and ripened from 3 to 18 months. Previous studies have examined their associated microbiota, identifying certain microorganisms (e.g., Brevibacterium, Corynebacterium, andStaphylococcus) highly represented throughout the ripening process. These taxa also exhibit high transcriptional activity, particularly in the degradation of milk components and the synthesis of organoleptic compounds. Within the framework of the MASTER EU-Consortium, 13 VB facilities were selected for sampling raw materials, final products, and food-contact- (FCS) and non-foodcontact surfaces (NFCS) in different production areas. The total DNA of the samples (n=269) was sequenced using shotgun sequencing. The effect analysis of the different areas over the cheese microbiota showed that the brine and the FCS-NFCS from ripening rooms highly influenced the VB rinds. However, the ripened VB cores maintained a distinct microbiota from their rinds andremained similar to that of fresh cheeses and processing FCS-NFCS, dominated by lactic-acid bacteria (starters cultures), among others. The functional analysis revealed the potential toproduce crucial organoleptic compounds such as diacetyl or propionate. The recovery of genomes directly from the metagenomes (MAGs) allowed the exploration of the functionalcontent of microorganisms present in the cheese. Some of these microorganisms have been isolated and are currently being tested in vivo on cheeses, to verify their impact on theorganoleptic and hygienic characteristics of VB.The bioinformatic analysis enabled the detection of additional features crucial for product quality and safety. Although ESKAPEE bacteria were found in processing areas, they were absent in thefinal products. However, a low overall presence of genes involved in the production of biogenic amines was detected, highlighting role of ripening in the quality and safety of cheese products.
