Resumen de Survey of yeast diversity during wine bottling processes using restriction analysis of 26S ribosomal DNA (rDNA)

M. M. Baleiras Couto, A.S. Gomes, M. Casal, F.L. Duarte

• Background and Aims: Microbiological stability of bottled wine is largely dependent on the bottling process as the last technological operation. In this survey, yeast contamination was monitored and characterised during wine bottling.

  Methods and Results: Samples of wine, apparatus surfaces and bottles were collected. Yeast counts were recorded and colony morphotypes were differentiated. Isolates were characterised by restriction enzyme digests of polymerase chain reaction amplified regions of 26S ribosomal DNA. For unknown patterns, DNA sequencing was performed. The presence of Zygosaccharomyces bailii and Torulaspora delbrueckii in the filling tubes was also confirmed in the final product. Another important point of contamination was the corker jaws.

  Conclusions: A great diversity of yeast species was found, indicating that these habitats are prone to microbial development.

  Significance of the Study: Evaluation of the level and diversity of yeast contamination during wine bottling allowed to alert producers for the need to evaluate and control microbial contamination.