## 4 Discussion
helveticus_ could have declined during ripening, it contributed to biochemical pathways characterizing the ripening of Caprino and Vaccino cheeses, thanks to its early cell autolysis, releasing peptidases and other enzymes [50; 51; 52]. In partial agreement with results from culture-dependent analyses, _S. equorum_ seemed to largely dominate the bacterial biota of Cacioricotta cheese object of the current study. This could be explained considering that, after cheese milk had undergone quite a drastic heat treatment that should have inactivated almost all microorganisms inhabiting raw milk, no starter culture was used. In these conditions, the manipulation of cheese by workers (surface dry-salting and daily overturning and washing) could have been one important driver of the microbial community. Given that staphylococci are found on the skin and mucosa of humans [53], the high abundance found for _S. equorum_ in the Cacioricotta cheese analyzed in this study could originate from human contamination. _S. equorum_ is a common component of the microbial communities of high-salt-fermented foods such as meat products and smear-ripened and semi-hard and hard cheeses [36; 54; 55]. Although this coagulase-negative staphylococcal species is regarded as a \"class of risk 2\" pathogen, several strains of _S. equorum_ acted as flavor and color enhancers of surface-ripened cheeses [56; 57; 58]. This species withstands relatively high salt concentrations (such as those encountered in Cacioricotta cheese), uses different carbon sources, and does not harbor gene coding for amino acid decarboxylase, related to release of biogenic amines [59]. Thus far, food-derived strains of _S. equorum_ did not show any pathogenic traits [60]. _S. thermophilus_ was the dominant bacterial OTU of Pecorino cheese. This result disagreed with the diversity of bacterial community (staphylococci and enterococci, and especially rod- and coccus-shaped LAB) of this cheese emerging from the culture-dependent analysis. In general, discrepancies between the results obtained from the two approaches could derive from some limitations inherent to the DNA-based approach, such as (i) different lysis efficiencies during extraction of DNA, (ii) preferential PCR amplification, and (iii) different numbers of copies of 16S rRNA operons among bacteria [61]. Considering that the Pecorino cheese analyzed in this study was manufactured using pasteurized milk and without starter cultures, we may hypothesize that _S. thermophilus_ could have considerably contaminated the equipment of the dairy plant [36; 62]. This bacterial species, originating from raw milk and/or starter cultures, could colonize the dairy environment, thanks to its capacity to produce biofilm [63; 64]. During cheese ripening, _S. thermophilus_ usually decreases over time [65; 66; 54]. However, it may still inhabit Pecorino cheese, at cell densities of 5-6 log CFU g\({}^{-1}\), even after 6-12 months of ripening [67; 68; 69]. Overall, the actual contribution of microbiota to the characteristics of the cheeses object of study remains hazy due to culture-independent analysis performed on DNA (instead of RNA) and only targeted at the _Firmicutes_ bacterial phylum. In this study, the highest peptidase activities were found in either Caprino or Vaccino cheeses, probably due to NWS cultures, which add microbial biomass and related enzyme activities to cheese [70]. In line with these findings, _L. helveticus_ as the dominant LAB species detected in Caprino and Vaccino cheeses can count on a potent proteolytic system producing short peptides and liberating FAA from the casein matrix [71]. Indeed, positive correlations were found between _L. helveticus_ and some variables related to the proteolysis level of chees. The lowest enzyme activities, found in Cacioricotta cheese, could be caused by the high salt concentration of this cheese. Indeed, an increase in salt concentration lowered some peptidase activities [72]. Contrarily, [PERSON] et al.