Safety and beneficial properties of bacteriocinogenic Pediococcus acidilactici and Pediococcus pentosaceus isolated from silage

The control of Listeria monocytogenes is a relevant goal for dairy products, a process that begins from the supply of feed and management of animals' health. In the present study, we evaluated the safety of two bacteriocinogenic Pediococcus strains and show that both can be considered as safe, based on their haemolytic activity, biogenic amine production and antibiotic resistance, all evaluated through phenotypical and biomolecular approaches. Both strains have shown potential as a producer of γ‐aminobutiric acid (GABA) and carry an incomplete set of genes related to folate biosynthesis; both strains were able to adhere to Caco‐2 cell lines with adhesion rates of 6·59% ± 3·73 and 0·84% ± 0·48. Laboratory prepared clover silage, inoculated with each bacteriocinogenic Pediococcus strain and contaminated with L. monocytogenes, proved the hypothesis for bioprotective effect of the tested strains, with the tested pathogen eliminated in the first 24 h of the experiment. These results indicate that evaluated strains can be potential beneficial candidates for application in silage production. Significance and Impact of the Study: We evaluated the safety and beneficial features of two bacteriocinogenic strains: P. acidilactici ST3522BG and P. pentosaceus ST3633BG. The concept ‘safety first’ needs to be the starting point in any proposal for application of new beneficial culture, although they belong to a species with historical safety record. Two evaluated Pediococcus strains were negative for biogenic amine production, haemolytic activity and antibiotic resistance according to performed physiological tests. At the DNA level, both strains generated negative results for the majority of the tested virulence genes, biogenic amines and vancomycin resistance genes. Apart from their safety, some beneficial properties of studied strains were evaluated, including their effectiveness in control of Listeria monocytogenes on silage model system, demonstrating successful inhibition of artificially added pathogen by both the Pediococcus strains.