## 4 Discussion  
Due to variations in ingredients and processing technologies, the geographical origin of fermented foods can have a profound impact on their technological properties and microbial diversity [3; 4]. This is also true for fermented meat products, where clear-cut differences have for instance been found in the characteristics of Northern and Southern European variants [5; 6]. The differences in technological properties, namely salt content and pH, of fermented meat products in the present study are in line with the findings of an earlier study, in which the same fermented meat products were investigated, albeit at another moment in time, thus representing other batches [6]. Generally, the salt content of European cured meat products differs within and across different countries [6; 47]. However, these differences are not expected to largely influence the technologically important microbiota, consisting mainly of LAB and CNS, as these microorganisms are commonly well adapted to high-salt levels [21]. The usual contrast in acidification extent between Northern and Southern European fermented meat products was illustrated by the differences in pH between German and Belgian commercial products, on the one hand, and French, Italian, and Spanish ones, on the other hand [6; 9; 11]. With respect to the microbial diversity, application of amplicon-based HTS methods allowed studying the microbial communities with greater resolution compared to previous culture-dependent studies [6; 25]. Sequencing of the V4 hypervariable region of the bacterial 16S rRNA gene showed that the genus _Lactobacillus_ was omnipresent in fermented meat products across all producing countries examined. Although the genus _Lactobacillus_ has recently been reclassified into 25 genera, of which _Latilactobacillus_ and _Lactiplantiobacillus_ contain the most relevant species for meat fermentation [48], the SILVA database used in the present study was not yet updated at the moment the bioinformatics analysis was performed, hence still _Lactobacillus_ is reported here. The presence of _Lactobacillus_ is not surprising as they are frequently encountered as one of the most important genera in fermented sausages, with multiple species such as _Latilactobacillus sakei_ (formerly known as _Lactobacillus sakei_), showing great adaptation to the meat matrix [21; 25; 49]. The presence of _Pediococcus_ in some Belgian and German fermented meat products might be a consequence of its addition as a starter culture, as pediococci, such as _P. pentosacus_, are sometimes added in Northern Europe and Northern America to hasten acidification under higher fermentation temperatures [6; 50]. Spanish fermented meat products were remarkable because of the presence of several uncommon genera, such as _Bacillus_, _Brochothrix_, _Carobacterium_, _Corynebacterium_, and _Tetragonococcus_. These species have nonetheless all been encountered previously to some degree in the natural microbiota of fermented meat products [51; 52; 53; 54; 55]. The fact that the genus _Staphylococcus_ was not encountered across all Belgian and German fermented meat product samples when targeting the V4 region, did not necessarily infer its absence, as differences in biomass and 16S rRNA copy numbers may cause less abundant genera to be under the detection limit [56; 57]. Indeed, whenever a substantial number of reads were ascribed to _Staphylococcus_, the MSA and MRS counts were comparable, with less than 1.0 log (cfu/g) of difference. Furthermore, high-throughput amplicon sequencing of a part of the _tuf_ gene revealed diversified CNS communities in all fermented meat products examined. The CNS communities in French and Italian fermented meat products demonstrated a high relative abundance of _S. xylosus_, which was almost always accompanied by _S. equorum_. Other CNS species, such as _S. carnosus_ and _S. saprophyticus_, were encountered intermittently and mostly in low relative abundances. This was in line with previous studies, where _S. xylosus_ and _S.