Cultivability of Streptococcus thermophilus in Grana Padano cheese whey starters.
The application of a culture-independent approach, that of reverse transcriptase-length heterogeneity-PCR coupled with epifluorescence microscopy, allowed us to observe that Streptococcus thermophilus is metabolically active, but only partially cultivable in Grana Padano cheese whey starters. A short preincubation of the starters in sterile skimmed whey was followed by cultivation in sterile skimmed whey-enriched M17. This procedure restored the cultivability of S. thermophilus and enabled us to detect S. thermophilus at ranges (10(7)-10(8) CFU mL(-1)) which have rarely been reported in these cultures. The use of cheese whey as a cultivation-revitalization substrate can be useful to obtain an unbiased picture of the microbial composition of whey starters for Grana Padano cheese, thus avoiding an underestimation of S. thermophilus in these cultures.
Istituto Sperimentale Lattiero Caseario, Lodi, Italy.
Maria Emanuela
ME
Fornasari
Lia
L
Rossetti
Domenico
D
Carminati
Giorgio
G
Giraffa
D001431:Bacteriological Techniques; D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D003470:Culture Media; D008856:Microscopy, Fluorescence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048249:Streptococcus thermophilus / Q000254:growth & development* / Q000378:metabolism
D003470:Culture Media