Selection of dominant NSLAB from a mature traditional cheese according to their technological properties and in vitro intestinal challenges.

Isolates (47) of lactobacilli from 5 different productions of Melichloro cheese were examined for potential use as adjunct cultures. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins classified 29 isolates as L. paraplantarum and 18 as L. paracasei subsp. paracasei. Randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis differentiated the L. paraplantarum and L. paracasei subsp. paracasei isolates at strain level and both, RAPD analysis and whole-cell protein profiling provided useful information about the diversity of nonstarter lactic acid bacteria (NSLAB) in the different cheese productions. The isolates were slow acidifiers and about 70% of them degraded, preferentially α(s)-casein. The amounts of amino acids accumulated in the milk increased with the incubation time. A similar enzyme profile was exhibited by strains of both species, except for α-mannosidase and α-fucosidase, which were not detected in the L. paracasei subsp. paracasei strains. All strains grew in the presence of bile at 0.3% and the majority was able to withstand pH 2.5 and pancreatin at 0.1%. Moreover, all strains reduced cholesterol in vitro, with higher removal ability recorded for strains of L. paraplantarum. A narrow spectrum of antibacterial activity was recorded for 88% of the strains. Selected isolates with appropriate technological and interesting in vitro intestinal challenges could be used as adjuncts and deserve further studies.