Rapid detection of Oenococcus oeni in wine by real-time quantitative PCR

ABSTRACT Aims: To develop a real-time polymerase chain reaction (PCR) method for rapid detection and quantification of Oenococcus oeni in wine samples for monitoring malolactic fermentation. Methods and Results: Specific primers and fluorogenic probe targeted to the gene encoding the malolactic enzyme of O. oeni were developed and used in real-time PCR assays in order to quantify genomic DNA either from bacterial pure cultures or wine samples. Conventional CFU countings were also performed. The PCR assay confirmed to be specific for O. oeni species and significantly correlated to the conventional plating method both in pure cultures and wine samples (r ¼ 0Æ902 and 0Æ96, respectively). Conclusions: The DNA extraction from wine and the real-time PCR quantification assay, being performed in ca 6 h and allowing several samples to be concurrently processed, provide useful tools for the rapid and direct detection of O. oeni in wine without the necessity for sample plating. Significance and Impact of the Study: Rapid quantification of O. oeni by a real-time PCR assay can improve the control of malolactic fermentation in wines allowing prompt corrective measures to regulate the bacterial growth.