Document Detail

A real-time PCR assay for the enumeration and detection of Zygosaccharomyces bailii from wine and fruit juices.
MedLine Citation:
PMID:  16950531     Owner:  NLM     Status:  MEDLINE    
Zygosaccharomyces bailii is a major food and beverage spoilage organism. Existing methods for its detection involve lengthy enrichment techniques and then the result does not always differentiate between Z. bailii and Saccharomyces cerevisiae. In this work, we developed a quantitative real-time PCR assay for the rapid detection of Z. bailii from fruit juices and wine even in the presence of non-target DNA. Primers were designed to the gene coding for the D1/D2 loop of the 26S ribosomal RNA subunit producing a single PCR product with a melting temperature of 83.5 degrees C. As few as 2 cells per ml could be detected by the assay in cranberry raspberry and apple juices and 22 cells per ml from grape juice. The assay was equally efficient in wine, detecting 6 cells per ml even in the presence of 10(7)S. cerevisiae cells. The CFU/ml as determined by plating on YM media showed excellent correlation with the CFU/ml established by the QPCR assay for all the beverages examined. Unknown samples of Z. bailii were prepared in the juices and wine and examined by QPCR. The QPCR estimated cell number was in good agreement with the cell counts obtained by plating, the exception being the cranberry raspberry juice sample. It was determined by live/dead cell counts that the Z. bailii cells were less viable in this juice thus leading to an overestimation of CFU/ml by QPCR. However, the correlation was high between QPCR and total cell count as determined by fluorescent microscopy. This assay provides a rapid and accurate method to establish the levels of the total Z. bailii population which consists of both viable and nonviable cells.
Helen Rawsthorne; Trevor G Phister
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-09-06
Journal Detail:
Title:  International journal of food microbiology     Volume:  112     ISSN:  0168-1605     ISO Abbreviation:  Int. J. Food Microbiol.     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-10-06     Completed Date:  2006-12-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8412849     Medline TA:  Int J Food Microbiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  1-7     Citation Subset:  IM    
3141 Chestnut Street, Department of Bioscience and Biotechnology, Stratton Hall, Drexel University, Philadelphia, PA 19104, USA.
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MeSH Terms
Beverages / microbiology*
Colony Count, Microbial
DNA Primers
DNA, Fungal / chemistry
Food Contamination / analysis*
Food Microbiology
Polymerase Chain Reaction / methods*
RNA, Ribosomal / analysis
Sensitivity and Specificity
Species Specificity
Wine / microbiology*
Zygosaccharomyces / isolation & purification*
Reg. No./Substance:
0/DNA Primers; 0/DNA, Fungal; 0/RNA, Ribosomal; 0/RNA, ribosomal, 26S

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