Effect of Plasma Nitriding Surface Modification on the Adhesion of Food Pathogens to Stainless Steel AISI 316 and AISI 304

Food pathogens like Salmonella spp. and Listeria monocytogenes can attach to surfaces commonly found in food processing environment, increasing the risk of foodborne diseases. Therefore, the use of effective strategies to reduce bacterial adhesion on equipment surfaces is a subject of great interest for food industries. The plasma nitriding treatment has been investigated for surface modification of biomedical materials, aiming to reduce bacterial attachment. However, this technology has not yet used in food equipment surfaces. The objective of this study was to evaluate the effect of plasma nitriding surface modification of stainless steels on the adhesion of S. Enteritidis and L. monocytogenes. Coupons of stainless steel AISI 316 and AISI 304 were treated with plasma nitriding (30 Pa, 100 W), and bacterial adhesion was compared with untreated coupons. Bacterial counts and surface hydrophobicity were analyzed before and after treatment. Results showed that plasma nitriding treatment modified the hydrophobicity of the stainless steel surfaces, and the number of attached cells was reduced when compared to untreated stainless steel coupons. Based on these results, plasma nitriding treatment may be a promising technology, which can be used to hinder bacterial attachment on stainless steel surfaces. Practical ApplicationsThe modification of stainless steel surfaces with plasma nitriding can influence on the bacterial adhesion, contributing with food safety. This surface treatment can be used in industrial scale before the manufacture of stainless steel equipment used in food industries. The use of equipment treated with plasma nitriding do not compromise food with chemical or physical residues, however, it should be used as an additional control measure to microbial hazards and do not substitute Good Hygiene Practices.