Prof. Dr. Helmut König,
Johannes Gutenberg University,
Inst. Microbiology and Wine Research,
Mainz,
Germany
Dr. Jürgen Fröhlich,
Erbslöh Geisenheim AG,
Geisenheim,
Germany
Prof. Dr. Gottfried Unden,
Johannes Gutenberg University,
Inst. Microbiology and Wine Research,
Mainz,
Germany