## 3 Results and Discussion
### Determination of the Microbiota of Edam Cheeses by High-Throughput Sequencing (HTS)
_Lactococcus_ and _Propionibacterium_ from starter cultures accounted for 56-65% of all bacteria, whereas _Leuconostoc_ represented only a fraction of percent of the overall microbial community. Similar results were reported by [PERSON] et al. [42]; in their study, the number of sequence reads for _Leuconostoc_ was also low. A predominance of starter bacteria was reported by [PERSON] et al. [16], who found that starter bacteria accounted for 85% of the microbiota in the core samples of Tomme d'Orchies cheese, and by [PERSON] et al. [41], who demonstrated that _Lactobacillus_ and _Streptococcus_ predominated in Grana-like cheese inoculated with natural whey starters (NWS). [PERSON] et al. [19] also found that _Lactococcus_, _Lactobacillus_, and _Propionibacterium_ bacteria accounted for 80-82% of the microbiota in industrially produced Swiss cheese. However, in a study by [PERSON] et al. [18], starter bacteria (_Lactococcus_, _Leuconostoc_, and _Lactobacillus_) represented more than 99% of the bacterial community in industrially produced Dutch cheese. Figure 2: The average relative abundance (%) of the sequences identified at genus level in samples of Edam cheese. The results of the SLAB and NSLAB analyses performed with the use of both methods (culture-dependent and NGS) revealed a certain regularity. When plate counts (expressed in log cfu/g) were one log unit higher in one bacterial genus than in another, the corresponding number of reads was approximately 10 times higher (Table 3 and Table S1). Despite the high proportions of starter bacteria in cheese samples, a high number of reads was noted for the NSLAB. In the phylum Actinobacteria, the abundance of _Cellulomonas_ in the microbial community was relatively high, and it ranged from 1% to 3% in all cheese samples. The genera _Bifidobacterium_ and _Leucobacter_ were less abundant, and their proportions were determined at 0.40%/0.94% and 0.18%/0.33%, respectively. The remaining identified genera of the phylum Actinobacteria accounted for up to 0.2% of the investigated microbial communities (Table S1). Spring cheese samples differed considerably from the remaining samples in the frequency of _Lactobacillus_, which was higher in spring samples (approximately 1.5%) (Table S1). In the genus _Lactobacillus_, the highest number of reads was obtained for _Lactobacillus rhamnus_, _Lactobacillus kefriarch_, _Lactobacillus kefriarch_, and _Lactobacillus casei_ (data not shown). The relative frequency of _Bifidobacterium_ and _Streptococcus_ was 0.6% and 0.3% higher, respectively, only in individual samples relative to the remaining cheese samples (0.08%) (data not shown). Similar results were reported in other studies of industrially produced cheeses. [PERSON] et al. [18] detected _Lactobacillus_ and _Streptococcus_ in Dutch-type cheese, and [PERSON] et al. [19] identified _Enterococcus_ and _Streptococcus_ in Swiss-type cheese. The phylum Firmicutes also includes bacteria that cause technological defects in cheeses. In the group of contaminating bacteria, the highest number of reads was obtained for spore-forming bacteria of the genus _Clostridium_. The relative proportions of _Clostridium_ were 0.97% higher in spring samples than in autumn samples. The genus _Clostridium_ was represented mainly by three species: _Clostridium__butyricum_, _Clostridium longisporum_, and _Clostridium tyrobutyricum_. In spring samples with the highest number of reads for the genus _Clostridium_, the predominant species was _C. tyrobutyricum_, whose abundance was around 10-fold higher in comparison with _C. butyricum_ and _C. longisporum_ in the remaining samples (data not shown). In the current study, next-generation sequencing supported the detection of _C. tyrobutyricum_, which could be responsible for late blowing, a cheese defect resulting from butyric acid fermentation [43; 44]. This is a very valuable observation that can be used to introduce the required adjustments during cheese production, ripening, and storage.