Antimicrobial activity of copper surfaces against biofilm formation by Salmonella Enteritidis and its potential application in the poultry industry

Abstract

As a consequence of developing antimicrobial resistance to disinfectants, copper, which exhibits antimicrobial activity, has been studied as a possible alternative to the use of stainless steel surfaces. The aim was to evaluate the antimicrobial activity of copper surfaces in preventing biofilm formation by Salmonella Enteritidis and to determine their corrosive capacity. Strains of S. Enteritidis were incubated at 4 °C, 12 °C, and 25 °C with 1 cm² coupons of electrolytic copper (99.9% Cu), brass (70% Cu), copper coated with tin, and stainless steel (control). A planktonic cell-suspension assay was used, followed by serial dilutions and bacterial counts. The corrosion test was performed with two disinfectants: benzalkonium chloride and sodium hypochlorite (100, 200, and 400 ppm). There was a significant reduction in biofilm production (log₁₀ CFU cm^-2) on the copper (2.64 at 4 °C, 4.20 at 12 °C, 4.56 at 25 °C) and brass (2.79 at 4 °C, 3.49 at 12 °C, 4.55 at 25 °C) surfaces compared to the control (5.68 at 4 °C, 5.89 at 12 °C, 6.01 at 25 °C). The antimicrobial surfaces showed uniform corrosion similar to that of surfaces generally used. These results demonstrated the effectiveness of copper surfaces in reducing S. Enteritidis and suggest they can be used as a complementary antimicrobial to control for this pathogen.

Keywords: Antimicrobial properties; Biofilm; Copper; Salmonella.