Identification and quantification of acetic acid bacteria in wine and vinegar by TaqMan–MGB probes

Abstract

A Real-Time PCR (RT-PCR) assay was developed using TaqMan minor groove binder (MGB) probes for the specific detection and quantification of five acetic acid bacteria (AAB) species ( Acetobacter pasteurianus, Acetobacter aceti, Gluconacetobacter hansenii, Gluconacetobacter europaeus and Gluconobacter oxydans) in wine and vinegar. The primers and probes, designed from the 16S rRNA gene, showed good specificity with the target AAB species. The technique was tested on AAB grown in glucose medium (GY) and inoculated samples of red wine and wine vinegar. Standard curves were constructed with the five target species in all these matrices. Quantification was linear over at least 5 log units using both serial dilution of purified DNA and cells. When this technique was tested in GY medium and inoculated matrices, at least 10 2–10 3 cells/ml were detected. To quantify low populations of AAB in microbiologically complex samples, a PCR enrichment including part of the 16S–23S rRNA gene ITS region was needed to increase the amount of target DNA compared to non-target DNA. The RT-PCR assay used in this study is a reliable, specific and fast method for quantifying these five AAB species in wine and vinegar.