Control of Listeria monocytogenes biofilm on industrial surfaces by cell ‐ free extracts of Lactobacillus plantarum

Abstract

In this study, the anti‐microbial and anti‐biofilm potential of the cell‐free extract (CFE) of Lactobacillus plantarum was assessed against Listeria monocytogenes 32 isolated from the food sample. CFE of L. plantarum showed high anti‐microbial activity (15.5 ± 1.4 mm diameter zone) against L. monocytogenes 32. The anti‐biofilm forming activity with the sub‐minimum inhibitory concentration (MIC) value of CFE (15.625 mg/L) for 24 hr co‐incubation period was obtained with the 90 ± 7.9% inhibition. Co‐incubation assay was also carried out on different surfaces such as stainless steel, polypropylene, and polyvinyl chloride. Viable cells in the formed biofilm were counted and the greatest reduction (5.22 log CFU/cm2) was achieved on polyvinyl chloride surface. Both biofilm formation and inhibition were also visualized by Scanning Electron Microscopy. It was observed that the biofilm of L. monocytogenes 32 was thread‐like, binding one cell to another and the surface by the extracellular polymeric substance. Practical applications The dairy, meat, poultry, and seafood industries are the main food sectors where the biofilm formation of food‐borne pathogens is observed. Listeria monocytogenes is one of the most noteworthy among them. High costs, procurement difficulties, or resistance problems limit the practical use of several approaches focused on the inhibition of L. monocytogenes biofilms. To prevent biofilm formation and/or to destroy cells embedded in biofilm via lactic acid bacterial strains and/or their metabolites has been remarkable in recent years. In the light of data obtained in this study, the cell‐free extract of L. plantarum with its anti‐microbial and anti‐biofilm activity may be used to design as a bio‐control strategy with its safe and environmentally friendly properties for prevention of biofilm formation of L. monocytogenes.

Use of Probiotics to Control Biofilm Formation in Food Industries

“…Chemical treatment with detergents, sanitisers, and disinfectants seems to be an effective biofilm control method [ 23 , 31 , 38 ]. Sodium hypochlorite, hydrogen peroxide, peracetic acid, and sodium hydroxide are chemical agents that have demonstrated competence in reducing biofilms [ 22 , 25 ].…”

“…Biofilm tolerance against synthetic antimicrobials and the negative consumer perception towards these chemicals, in addition to their release into the environment and the high amount of water spent in cleaning, have strengthened the search for different alternatives, namely for environmentally friendly disinfection [ 25 , 32 ]. Environment-friendly biofilm control strategies include the use of enzymes, bacteriophages, natural compounds such as essential oils, and bacterial products such as bacteriocins and biosurfactants [ 31 , 38 ]. Enzymes (e.g., proteases, lipases, and polysaccharidases) are biodegradable and low-toxicity bioactive macromolecules that have shown the ability to inhibit biofilm formation.…”

Combating biofilms of foodborne pathogens with bacteriocins by lactic acid bacteria in the food industry

“…The low efficacy of nisin against mature biofilms was also shown by Henriques and Fraqueza (2017) who found that nisin at the concentration of 25-400 IU/ml was not active in 5-day biofilms formed by L. monocytogenes isolated from meat products food chain and the estimated LD 90 values ranged from 1000 to 3000 IU/ml for most strains in biofilms. (Yi et al, 2018a;Qiao, Zhang, et al, 2021), Lactobacillus curvatus (Camargo et al, 2016;Melian et al, 2019), and Lactobacillus plantarum (Kıran et al, 2021;Pei et al, 2020). Winkelströter et al (2011) reported that cell counts of L. monocytogenes adhered to stainless steel (SS) coupons were decreased lower than 3.0 log CFU/cm 2 in the presence of neutralized CFS of L. sakei 1 containing sakacin 1 for 24 h. However, the authors observed re-growth of adhered cells in the presence of CFS after 48 h, possibly due to the lack of competition for nutrients or selection of bacteriocin-tolerant strains.…”

“…Bacteriocins produced by Lactobacillus spp., known as class II bacteriocins with thermostability and activity at a wide pH range, have been frequently isolated from fermented foods (Abdulhussain Kareem & Razavi, 2020; da Silva Sabo et al., 2014). Antibiofilm activity of bacteriocins against Gram‐positive foodborne pathogens such as L. monocytogenes and S. aureus has been demonstrated among strains belonging to Lactobacillus sakei (Pérez‐Ibarreche et al., 2016; Winkelströter et al., 2011), Lactobacillus crustorum (Yi et al., 2018a; Qiao, Zhang, et al., 2021), Lactobacillus curvatus (Camargo et al., 2016; Melian et al., 2019), and Lactobacillus plantarum (Kıran et al, 2021; Pei et al., 2020). Winkelströter et al.…”