Simulation of Listeria monocytogenes bacterial deposits in pitting corrosion on stainless steel grade 304

This study investigated and simulated the pitting corrosion on stainless steel grade 304 with a thickness of 1.5 mm and a 2B finish, using 3.5% NaCl solution electrochemically to generate the pits. The diameters of the pits on the sample surface were measured by optical microscopy and the average pit diameter varied over time as pit growth progressed. All the samples were incubated for five days to allow Listeria monocytogenes bacterial deposits in the pits. SEM images showed bacteria in small clusters in pits formed by pitting corrosion on the stainless steel surface, also within the smallest pits with pit mouth diameters of
18 μm. The diameter of the pit mouth was significantly positively correlated with the number of bacteria deposited. These findings suggest that pitting corrosion on stainless steel surfaces can create a habitat for bacteria. This has implications particularly for the food industry, where stainless steel is commonly used in equipment and facilities for food processing and storage. Effective control measures are necessary to prevent the colonization by bacteria of pitting corrosion on stainless steel
surfaces.