Bactericidal action of oleuropein extracted from green olives against Lactobacillus plantarum

The phenolic compound oleuropein extracted from green olives was shown to be bactericidal against nine strains of Lactobacillus plantarum isolated from green olive fermentation brines. Heat‐treated oleuropein also demonstrated a strong bactericidal effect but not alkali‐treated oleuropein, which allowed survival of most of the strains tested. The bactericidal effect was accompanied by changes in the typical bacillary structure and Gram‐positive stain of L. plantarum.