Abstract:

The dynamic changes of Lactococcus lactis in pickled Ma bamboo shoots with 6 g/100 mL salt concentration were
studied by quantitative real-time polymerase chain reaction (qRT-PCR). After the DNA extraction from standard Lactococcus
lactis, preparation of positive plasmids, protraction of standard curve, DNA extraction from samples at different fermentation
stages and qRT-PCR, and quantitative detection were performed. The results showed that during fermentation (0–63 days),
the concentration of Lactococcus lactis increased gradually from 2.41 × 102 copies/μL (day 0) to the maximum value of
4.63 × 108 copies/μL (day 14), an increase by six orders of magnitude, followed by a slow decrease to 5.02 × 106 copies/μL
at day 63. In conclusion, qRT-PCR technology provides a reliable, fast and effective way for the quantitative analysis of
bacteria in pickled Ma bamboo shoots.

Key words: Ma bamboo shoots (Dendrocalamus latiflorus), pickling, quantitative real-time polymerase chain reaction (qRT-PCR), Lactococcus lactis, dynamic changes