Lowering histamine formation in a red Ribera del Duero wine (Spain) by using an indigenous O. oeni strain as a malolactic starter

- Histamine is produced in Tempranillo wines during MLF, and could reach final levels over 35 mg/L in non-inoculated wines.
- The species responsible for the synthesis of histamine in this winery is O. oeni.
- Both O. oeni producing and non-producing histamine strains were present (40% of producers).
- Histamine accumulation has been lowered 5 times by inoculating an autochthonous O. oeni strain.

This study demonstrates for the first time that a non-commercial selected autochthonous O. oeni strain has been used to conduct malolactic fermentation (MLF) while lowering histamine formation in the same winery. Lactic acid bacteria (LAB) were isolated from 13 vats before and after spontaneous MLF at the Pago de Carraovejas winery from the Ribera del Duero region (Spain). Only O. oeni were present, typed and characterized, and both histamine producer and non-producers existed. From the non-producers, one strain was selected to become a starter according to its genetic profile, prevalence in the different wines in the winery, resistance to alcoholic degree, resistance to high polyphenolic content, inability to synthesise histamine, growth kinetics and malolactic activity. This starter was produced at semi-industrial levels to inoculate 20,000 L of Tempranillo red wine. The inoculated vat showed 5-fold less histamine than the non-inoculated control vat. After 1 year, the barrel-ageing histamine concentrations were 3-fold lower in the inoculated vat than in the non-inoculated vat.