Aims: To develop rapid methods allowing enumeration of lactic acid bacteria producing biogenic amines in wines and to analyse wine samples by the methods.
Methods and results: Methods based on quantitative PCR targeting bacterial genes involved in histamine, tyramine and putrescine production were developed and applied to detect and quantify the bacteria producing these biogenic amines in wine. Analysis of 102 samples revealed low populations of the targeted bacteria in grape must samples, an increased bacteria biomass in wine samples after alcoholic fermentation, reaching the highest population levels (above 10(6) cells ml(-1)) during spontaneous malolactic fermentation. A minimum of 10(3) ml(-1) producing cells was required for production of more than 1 mg l(-1) of biogenic amines. Accumulation of putrescine in wine was correlated with the presence of bacteria carrying an ornithine decarboxylation pathway. Trials of winemaking showed that the use of selected bacteria for inducing malolactic fermentation was efficient to limit the proliferation of undesirable bacteria and the production of biogenic amines.
Conclusion: Methods using quantitative PCR are efficient to enumerate biogenic amines-producing cells in wine.
Significance and impact of the study: The methods can help to better control and to improve winemaking conditions in order to avoid biogenic amine production.