Bacteria were maintained at −80 °C and resuscitated in M17 broth
(Difco) containing 2% lactose or glucose (w/v) for S. thermophilus, S.
salivarius, and L. garvieae and in MRS broth (Difco) for all Lactobacillus
species. The cultures were incubated at 37 °C and 30 °C for thermophilic
and mesophilic species, respectively. The identification of isolates
at the species level was performed by means of 16S rDNA gene
sequencing. The sequences of the primers used for the amplification
of the 16S rDNA gene were P0 and P6, and the PCR protocol described
by the authors was used (Di Cello and Fani, 1996). S. thermophilus and
S. salivarius strains were identified by secY gene sequencing (Pombert
et al., 2009). The PCR products were purified using an UltraClean DNA
Purification Kit (MO BIO). Finally, sequence comparison was performed
with Genetics Computer Group sequence analysis software
using BLAST.