Development and characterization of anti-biofilm coatings applied by Non-Equilibrium Atmospheric Plasma on stainless steel

• Published in: Food research international Vol. 152; p. 109891
• Main Authors: Fernández-Gómez, Paula, Muro-Fraguas, Ignacio, Múgica-Vidal, Rodolfo, Sainz-García, Ana, Sainz-García, Elisa, González-Raurich, Montserrat, Álvarez-Ordóñez, Avelino, Prieto, Miguel, López, Mercedes, López, María, Toledano, Paula, Sáenz, Yolanda, González-Marcos, Ana, Alba-Elías, Fernando
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01.02.2022
• Subjects: Anti-biofilm coatings; Atmospheric pressure cold plasma; Biofilms; Food Microbiology; Food-Processing Industry; Hydration layer; Listeria monocytogenes; Plasma-polymerization; Stainless Steel; Surface modification; Surface modification; Stainless steel; Anti-biofilm coatings; Hydration layer; Listeria monocytogenes; Atmospheric pressure cold plasma; Plasma-polymerization
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2020.109891

[Display omitted] •Anti-biofilm coatings were plasma-polymerized on stainless steel surfaces.•The best coatings combined two layers (2 precursors): a base and an upper functional.•The biofilm production by Listeria monocytogenes was reduced by 90%.•The best anti-biofilm effects were achieved at 12 °C (food processing conditions).•Low roughness and high hydrophilicity can reduce L. monocytogenes adhesion. Biofilm-mediated microbial persistence of pathogenic and spoilage bacteria is a serious problem in food industries. Due to the difficulty of removing mature biofilms, great efforts are being made to find new strategies to prevent bacterial adherence to surfaces, the first step for biofilm development. In this study, coatings of (3-aminopropyl)triethoxysilane (APTES), tetraethyl orthosilicate (TEOS) and acrylic acid (AA) were applied by Non-Equilibrium Atmospheric Plasma on stainless steel (SS) AISI 316, the SS most commonly used in food industry equipment. Their anti-biofilm activity was assessed against Listeria monocytogenes CECT911 and Escherichia coli CECT515 after incubation at 37 °C. The best results were obtained for L. monocytogenes, with coatings consisting of a base coating of APTES and a functional coating of TEOS (AP10 + TE6) or AA (AP10 + AA6) that reduced biofilm production by 45% and 74%, respectively, when compared with the uncoated SS. These coatings were further characterized, together with a variation of the best one that replaced the acrylic acid with succinic acid (AP10 + SA6). Their anti-biofilm activity was assessed under different incubation conditions, including two strains of L. monocytogenes isolated from processing environments of a meat industry. The coating AP10 + AA6 reduced the biofilm formation by 90% after incubation at 12 °C, a temperature more representative of those commonly found in food processing environments. The morphological and physico-chemical characterization of the selected coatings showed that the coating with the highest anti-biofilm activity (i.e., AP10 + AA6) had lower surface roughness and higher hydrophilicity. This suggests that the formation of a hydration layer prevents the adherence of L. monocytogenes, an effect that seems to be enhanced by low temperature conditions, when the wettability of the strains is increased.