###### Abstract  
This study focused on the characterization of lactic acid bacteria (LAB) in a renowned traditional Italian cheese, Pecorino di Farindola, in order to select an autochthonous culture and investigate its potential for the improvement of safety and functional properties. Two hundred and six LAB isolated throughout production and maturation from nine cheese lots of three farms were identified by 16S rRNA gene sequencing and tested for the presence of genes encoding virulence factors, vancomycin resistance (for enterococci), biogenic amines (BAs) and bacteriocin production for antimicrobial activity; and for the capacity to survive in the gastrointestinal tract (GIT) based on tolerance to low pH and bile salts and adhesion to CaCo-2 cells. A _Lacticaseobacillus paracasi_ isolate was used in cheese making and determined a decline of spiked _Liberia monocytogenes_ and _Escherichia coli_ O157 faster than in the control cheese. The autochthonous bacterial groups were numerically unaffected, apart from lactobacilli that were recovered in higher numbers in cheese with the addition of the _L. paracasi_ strain. Based on repetitive extragenic syndrome (Rep) polymerase chain reaction (PCR) profiles, the added strain possibly dominated until day 88 in the cheese. Results encourage further trials with autochthonous cultures in order to efficiently inhibit hazardous bacteria and to enrich a functional microbiota in Pecorino di Farindola and similar cheeses. Previous studies have provided evidence of the presence of high amounts of biogenic amines (BAs) in this cheese, mainly tyramine, whose formation was primarily attributed to the amino acid decarboxylase activity of enterococci and _Enterobacteriaceae_. However, a correlation between the composition of cultivable microbial groups and BA content could not be established [5]. The high BA content in this cheese is favoured by the use of pig rennet that is unique for its production process [6]. In this and other similar products, the antagonistic actions exerted by naturally occurring lactic acid bacteria (LAB) have a preeminent role in preventing the growth of undesired and pathogenic microorganisms. However, variability in the composition of the indigenous microbiota can cause instability in the safety promoting activities of LAB. The use of added cultures selected among autochthonous LAB could improve safety without modifying the typical manufacturing process and sensory characteristics [7]. Therefore, in this study, the LAB microbiota of Pecorino di Farindola cheese was characterized in order to select strains devoid of hazardous traits, which are able to persist during ageing and to antagonize pathogens, to be used in cheese making trials. Conventional bacterial counts were used to provide a quantitative estimate of the cultivable bacteria that predominated, mostly impacted biochemically changes in the cheese during maturation and were ingested with the product. In addition, this allowed isolation of LAB strains for further characterization. LAB isolated at the end of cheese maturation were also assessed for the prerequisites for survival in the gastrointestinal tract (GIT). In fact, traditional cheese is recognized as a good source of LAB able to colonize GIT that could confer functional properties to the product if able to exert probiotic actions [8]. LAB isolates, including enterococci, were obtained during cheese maturation from nine lots manufactured by three producers. These were screened by polymerase chain reaction (PCR) for genes encoding the production of nisin and other lantibiotics, as a bacteriocin class with broad inhibitory spectrum and therapeutic potential [9], enterocins, enterococcal virulence factors and vancomycin resistance genes and BA production. Moreover, isolates from cheeses at the end of ripening, which are those ingested by consumers, were evaluated for tolerance to low pH and bile salts, adhesion to intestinal CaCo-2 cells and production of antibacterial substances.