Impact of Lauric Arginate Application Form on its Antimicrobial Activity in Meat Emulsions

Lauric arginate (LAE) is a food-grade cationic surfactant that is highly active against a wide range of food pathogens (Listeria monocytogenes, Salmonella, and Escherichia coli) and food spoilers (Lactobacilli, yeast, and molds). The antimicrobial efficacy of LAE in compositionally complex environments is likely to be negatively impacted by its interactions with food ingredients. Therefore, we investigated different application systems of LAE and their impact on its antimicrobial efficacy when added to “Lyoner style” sausages. LAE was applied as a powder, aqueous solution, in oil-in-water emulsions with different droplet sizes, and as solid lipid particles (SLP) with different droplet sizes. Structures of the systems were identified by optical microscopy, differential scanning calorimetry (DSC) and static light scattering. A recontamination on the surface of sliced sausages was simulated using Listeria innocua as the target organism (2 log colony forming units (CFU)/slice), and the antimicrobial impact of 1,000, 1,500 and 2,000 μg/g applied LAE in the sausage was examined by growth curves. A modeling of the CFU-time relationship was carried out to provide a better evaluation of the antimicrobial activity of LAE. Finally, we carried out an isothermal titration calorimetry (ITC) analysis to simulate the interactions between LAE and proteins in the sausage matrix. Results revealed that the application systems differed in their surface area and, therefore, showed different antimicrobial activities when incorporated into sausage. The study demonstrated that the SLP and emulsions as LAE application systems increased the antimicrobial activity against microbial growth on the surface of sliced “Lyoner style” sausages.