Currently, the health benefts of probiotic bacteria are well known, and this has taken up a great deal of space in food science and health, both research and operational. On the other hand, anti-bioflm properties on food pathogens in the food and pharmaceutical industries have created an attractive challenge. This study aimed to describe the inhibi- tory activity of cell-free supernatants (CFS), planktonic cells, and bioflm form of lactobacilus strains (L. rhamnosus and L. plantarum) against food pathogens such as Pseudomonas aeruginosa and Listeria monocytogenes. Anti-bacterial activities of the CFS of lactobacillus strains were assessed by the microplate method and via violet staining. Evalua- tion of the antagonistic activity of planktonic cells and bioflm of LAB were performed by the spread plate method. The results showed the incubation time of 48 h was the best time to produce bioflm. Although the planktonic states reduce the pathogens bacterial about 1 –1.5 log, but in bioflm forms, decreased L. monocytogenes about 4.5 log compared to the control, and in the case of P. aeruginosa, a growth reduction of about 2.13 log was observed. Furthermore, bioflm formation of L. monocytogenes in the presence of L. rhamnosus cell-free supernatant was more weakly than L. plantarum CFS, but their CFS efect on reducing the bacterial population of P. aeruginosa was the same. According to the study, bioflm produced by probiotic strains can be considered a new approach for biological con- trol. Also, cell-free supernatant can be used as postbiotic in the food and pharmaceutical industries.

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