Inhibitory effects of probiotic potential lactic acid bacteria isolated from kimchi against Listeria monocytogenes biofilm on lettuce, stainless-steel surfaces, and MBEC™ biofilm device

Probiotics show great promise as alternative and environmentally friendly candidates to control microbial pathogens. Here, six isolated lactic acid bacteria (LAB) were chosen based on their anti-listerial activity. Anti-listerial LAB isolates were identified by 16S rRNA gene sequencing. The anti-listerial activities of these isolates were evaluated by Listeria monocytogenes biofilm inhibition assays on stainless-steel coupons (SS), lettuce, and a minimum biofilm eradication concentration (MBEC™) biofilm device. Results revealed that following co-culture with LAB for 24 h, L. monocytogenes biofilm cells were inhibited by up to 2.17 log CFU/cm2, 1.62 log CFU/cm2, and 1.09 log CFU/peg on SS, lettuce, and MBEC™, respectively. Although these LAB bacteria suppressed L. monocytogenes biofilm formation on both surfaces, the inhibitory effect on lettuce surfaces was lower than that on SS. These results support the potential use of LAB strains to inhibit biofilm formation by pathogenic bacteria on vegetable products and in the food industry, without associated risk to consumers. •Six lactic acid bacteria (LAB) from kimchi showed promise as antimicrobials.•The LAB suppressed L. monocytogenes biofilms on stainless steel, lettuce, and MBEC™ biofilm device.•The LAB isolates can be used to inhibit biofilm formation in food industries.•The LAB isolates pose little risk to consumers and are eco-friendly.