Study of the authenticity of commercial wine yeast strains by molecular techniques

mtDNA restriction analysis has been carried out with 45 different commercia l Saccharomyces wine yeast strains. The analysis with Hinf I provided uniqu e profiles for 17 of the 45 strains and can therefore be considered as indi vidual strains. Nevertheless, among the remaining 28 strains, only eight mt DNA restriction patterns appeared. These strains were subjected to electrop horetic karyotyping and PCR amplification of delta sequences. We concluded that the maximum discriminatory power was obtained when the results of the three techniques were combined, giving 13 different composite patterns for the 28 strains under study. The results showed evidence of mistakes during production or fraudulent practices by yeast producers, since only 30 indivi dual strains have been identified among the 45 Saccharomyces wine yeast str ains commercialised by different companies. Additionally, commercial starte rs of Saccharomyces uvarum and Saccharomyces bayanus have been re-identifie d as Saccharomyces cerevisiae. (C) 2001 Elsevier Science B.V. All rights re served.