Aims: The aim of this study was to test and locate the in vitro anti‐Helicobacter activity of seven Lactobacillus strains belonging to Lactobacillus plantarum group.

Methods and Results: Growth inhibition of H. pylori was tested using a well‐plate assay. Of the strains displaying the strongest growth inhibition, a L. plantarum isolated from sauerkraut (MLBPL1) was chosen for further studies. The detected anti‐Helicobacter activity of MLBPL1 was mainly associated with cell wall, and to a minor extent with the culture supernatant. The active component, which was determined to be between 3 and 10 kDa in size, retained its activity after 10 min treatment at 100°C. The activity was present when MLBPL1 was cultivated in rich laboratory cultivation medium MRS and in different food matrices.

Conclusions: The strains belonging to L. plantarum group showed anti‐Helicobacter activity in vitro. The main activity seemed to be associated with cell wall rather than culture supernatant or intracellular fraction.

Significance and Impact of the Study: In view of the rapid spread of resistant H. pylori strains caused by antibiotic therapy, addition of a fermented food containing L. plantarum to the conventional antibiotic treatment of Helicobacter infection could establish a potential complementary means to suppress the infection.