Antibiofilm Properties of a Plantaricin J-Containing Culture Supernatant from Lactiplantibacillus plantarum AV3: Potential for Inhibiting and Reducing Bacterial Biofilms on Food-Contact Surfaces

Abstract

Biofilm-forming foodborne pathogens are persistent contaminants on food-contact surfaces, and natural antimicrobials may provide adjunctive control strategies. This study characterized an antimicrobial peptide produced by Lactiplantibacillus plantarum AV3, isolated from Thai fermented fruit, and evaluated the antibiofilm activity of the neutralized plantaricin J-containing cell-free supernatant. The principal antimicrobial compound was purified by chromatography and identified by LC-MS/MS as plantaricin J. Purified AV3-derived plantaricin J displayed rapid and potent bactericidal activity against key Gram-positive foodborne pathogens, particularly Listeria monocytogenes (MIC = 0.003 mg/mL), and also inhibited the Gram-negative pathogen Salmonella enterica serovar Typhimurium (MIC = 0.012 mg/mL). Its stability under heat, broad pH range, and tolerance to organic solvents further support its applicability across diverse food systems. While a gradual decline in activity occurred during extended cold storage, effective inhibition persisted for up to two months, depending on the target organism. Importantly, the neutralized plantaricin J-containing supernatant (1 mg protein/mL; approximately 0.625 μg/mL purified plantaricin J activity-equivalents) exhibited dual antibiofilm activities, both preventing biofilm formation and reducing the viable cells in pre-formed biofilms on stainless steel, silicone tubing, and rubber by approximately 3.0 log CFU/8 cm² for L. monocytogenes and 1.0 log CFU/8 cm² for S. Typhimurium. These findings identify AV3-derived plantaricin J as a stable bactericidal peptide and its culture supernatant as a promising biofilm-reducing preparation, particularly against L. monocytogenes. Further validation using commercial sanitizer controls, mixed-species biofilms, and industrially relevant conditions is warranted.