This work evaluated the effect of adjunct autochthonous cultures on the chemical, microbiological and sensory characteristics of Fiore Sardo cheese during ripening. A total of twelve batches of cheeses were manufactured according to the technical Disciplinary of Fiore Sardo cheese, with and without different combinations of autochthonous strains isolated from the native microflora of artisanal Fiore Sardo. There were no significant differences in the cheese compositional parameters between experimental and control cheeses, but the addition of cultures led to a statistically significant decrease in pH values in experimental cheeses. The evolution of total mesophilic bacteria, total coliforms and lactic acid bacteria were significantly influenced by the addition of autochthonous cultures in most of the experimental cheeses. As for sensory characteristics, all the experimental cheeses reported significantly higher scores especially for shape, texture, interior openings, taste and aftertaste. This study demonstrated the beneficial effect of the addition of selected autochthonous cultures in accelerating the disappearance of undesirable flora and improving the typical sensory characteristics of the cheese, and confirmed the importance of ewes' milk as a source of technologically interesting strains that could be used to ensure a higher quality of artisanal cheese productions.

A total of 118 enterococcal strains isolated from artisanal Fiore Sardo cheese were characterized technologically and genetically. The presence of potential virulence factors was also investigated. Strains were classified as Ec. faecium (84 strains), Ec. durans (24 strains) and Ec. faecalis (10 strains). RAPD-PCR analysis with two different primers (M13 and XD9) confirmed species identification and proved useful for the detection of interstrain variations, especially among Ec. faecium isolates. Most strains could hydrolyse casein and had weak acidifying activity in milk. None of the isolates produced lipolytic reactions. Gelatinase activity was observed in two strains of Ec. faecalis and one strain of Ec. durans. β-Haemolysis on horses' blood was never detected in any of the strains, independently of species. Most strains produced tyramine from tyrosine but none decarboxylated lysine, histidine or ornithine. Overall, a wide spectrum of resistance was observed. Almost all strains were resistant to the aminoglycosides, gentamycin, kanamycin, streptomycin, neomycin, and to the semisynthetic penicillin, oxacillin, but resistance to vancomycin was not widespread among our strains: only one Ec. faecium and one Ec. durans strain were found to be vancomycin resistant. Our results show a certain diversity in technological traits of the enterococcal strains isolated from artisanal Fiore Sardo, together with a low incidence of some potentially pathogenic traits of health concern.