Open AccessCultivability of Streptococcus thermophilus in Grana Padano cheese whey starters
Author(s) -
Fornasari Maria Emanuela,
Rossetti Lia,
Carminati Domenico,
Giraffa Giorgio
Publication year - 2006
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00155.x
Subject(s) - streptococcus thermophilus , food science , skimmed milk , bacteria , biology , chemistry , lactobacillus , genetics , fermentation
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.