Population Dynamics of Lactobacillus helveticus in Swiss Gruyère-Type Cheese Manufactured With Natural Whey Cultures

Abstract

Lactobacillus helveticus, a ubiquitous bacterial species in natural whey cultures (NWCs) used for Swiss Gruyère cheese production, is considered to have crucial functions for cheese ripening such as enhancing proteolysis. We tracked the diversity and abundance of L. helveticus strains during 6 months of ripening in eight Swiss Gruyère-type cheeses using a culture-independent typing method. The study showed that the L. helveticus population present in NWCs persisted in cheese and demonstrated a stable multi-strain coexistence during cheese ripening. With regard to proteolysis, one of the eight L. helveticus populations exhibited less protein degradation during ripening.

Long read-based de novo assembly of low complex metagenome samples results in finished genomes and reveals insights into strain diversity and an active phage system

“…Furthermore, our results show that the complexity of our NWC metagenome samples was even lower than implied by previous studies [50]. The absence of L. helveticus in NWC_1 was particularly striking, since this species is thought to play an essential role in the production of Swiss Gruyère [49,51]. The presence of L. helveticus strains results in the reduction of the cheese bitterness (due to their proteolytic activity) [52], as well as in a faster ripening and enhanced flavor development , which are desirable effects in the production of cheese [53,54].…”

“…Within undefined cheese starter culture communities there are usually multiple strains per species with only a few being dominant [49]. Our long read-based approach could identify all dominant members of the community and the targeted survey based on 16S rRNA amplicon data resulted in the detection of only a few, additional very low abundant taxa, which are presumably of minor importance in our samples.…”

Long-read based de novo assembly of low-complexity metagenome samples results in finished genomes and reveals insights into strain diversity and an active phage system

“…Within undefined cheese starter culture communities there are usually multiple strains per species with only a few being dominant [51]. Our long-read based approach could identify all dominant members of the community and the targeted survey based on 16S rRNA amplicon data resulted in the detection of only a few, additional very low-abundance taxa, which are presumably of minor importance in our samples.…”

“…Furthermore, our results show that the complexity of our NWC metagenome samples was even lower than implied by previous studies [52] . The absence of L. helveticus in NWC_1 was particularly striking, since this species is thought to play an essential role in the production of Swiss Gruyère [51, 53]. The presence of L. helveticus strains results in the reduction of the cheese bitterness (due to their proteolytic activity) [54], as well as in a faster ripening and enhanced flavor development, which are desirable effects in the production of cheese [55, 56].…”

Investigation of the Lactic Acid Bacteria in Kazak Cheese and Their Contributions to Cheese Fermentation

“…During the cheese fermentation process, proteases from microorganisms degrade the proteins in milk and produce large amounts of peptides that can be further degraded into small peptides and FAAs (Niro et al, 2017;Moser et al, 2018). The concentration of different FAAs in cheese depends on the milk, starter, rennet, ripening conditions, and time of maturation (Tavaria et al, 2003;Tofalo et al, 2015;McCarthy et al, 2017;Zhou et al, 2018).…”