## 4 Discussion
A more accurate answer to the question of whether the probiotic strain used has developed, survived, and dominated the natural microflora in the meat environment can be obtained by combined culture-dependent and culture-independent methods, i.e., genetic engineering methods, including, for example, DNA polymerase chain reactions (PCR) or sequencing of the 16S rRNA (ribosomal ribonucleic acid) gene characteristic of LAB bacteria [5; 9; 32]. In our study, a specific pair of primers for PCR reaction was used, designed to the V1 region of the 16S rRNA gene, which enables the differentiation of the _Lacticaseibacillus rhamnosus_ species even from the closely related _L. casei_ group [24]. The results of the plate count agar method showed a high overall LAB count in the tested meat products. It was found that approximately 90% of all LAB in the meat matrix was _L. rhamnosus_. Taking into account that _L. rhamnosus_ is not a common species connected with the meat matrix, it can be concluded that the production technology designed in the laboratory and then scaled to the industrial conditions of dry fermented pork lions and sausages enabled the optimal growth and survival of the probiotic _L. rhamnosus_ LOCK900 bacteria for 12 weeks from the end of the production process. The developed dry fermented meat products can be classified as functional foodstuffs. One of the most important factors determining the quality and microbiological safety of food products is the conditions under which they were produced [13; 33; 34]. Health safety is the first criterion that a new food product must meet. In the second place is the definition of its quality. This problem is exacerbated when the developed food production technology is transferred from a laboratory and semitechnical conditions to industrial plants. Particular attention should be paid to products of animal origin, including raw products. Most pathogens that play a role in food-borne diseases are of animal origin [35]. The main problem in food hygiene is the contamination of raw meat material with pathogenic bacteria from the _Enterobacteriaceae_ family, such as _Salmonella_ spp., _Escherichia coli_, _Proteus_, and _Klebsiella_[36; 37]. Noteworthy is also the pathogen _Listeria monocytogenes_, especially important in the case of ready-to-eat products of animal origin [33; 34]. In the conducted studies, the total number of bacteria belonging to the _Enterobacteriaceae_ family (ENT) was determined as a microbiological indicator of the hygienic state of the study meat products and, thus, the hygiene of the industrial production process. Microbiological analyses have shown a significant difference between the number of ENT in all study samples of loins and sausages during 12 weeks of storage. Based on the results, it was shown that there is a better bio-conserving effect of LAB, especially in the loins and sausages with probiotic starter culture LOCK900. The addition of probiotic starter culture LOCK900 had a positive effect on inhibiting the number of _Enterobacteriaceae_ in the product and, finally, on eliminating them from the product. This dependence was observed in the control samples (native LAB microflora) until the 12 th week of the study. This relationship is explained by other authors like a bio-conserving effect of lactic acid bacteria on meat products [18; 38]. For example, [PERSON] et al. [26] also showed that the number of _Enterobacteriaceae_ in cured neck with LOCK900 addition decreased during the ripening and storage process (\(<1.0\) log cfu g\({}^{-1}\)). Whereas, [PERSON] et al. [39] showed that the effects of type and number of used starter lactic acid bacteria on the production of dry fermented sausages ensured the health safety of the product. Lack of _S. aureus, E. coli_, and _Enterobacteriaceae_ in all of the study sausages after six months of refrigeration is indicative of the extensive microbiological stability of the products. However, according to [PERSON] et al.