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.