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Galvanized steel is often used in the food industry due to its durability, strength, and lower cost relative to stainless steel. Herein, we report a coating method for galvanized steel that exhibits superhydrophobicity and antifouling capabilities, effectively inhibiting the attachment of fungi, bacteria, and mud. This coating was fabricated through a two-step process involving the immobilization of silica nanoparticles and subsequent chemisorption of an organosilane layer with low surface energy. The resultant coating yielded a static water contact angle of 157 ± 3.6°. Over a period of seven days, this coating achieved log10 reductions of 2.6 ± 0.1 and 2.9 ± 0.1 in the attachment of the bacterial strains of Salmonella enterica and Listeria innocua , respectively. Additional testing revealed a marked reduction in adherence of Aspergillus niger fungus. Following immersion in mud, coated surfaces showed an evident reduction in mud attachment in comparison to the original steel surfaces. Specifically, when tested with mud with a viscosity of ∼90,000 cP, the mud attachment percentage for the untreated steel surfaces and the coated steel surfaces was quantified as 94.57 ± 1.64% and 6.81 ± 2.43%, respectively. The electrochemical characterization of the coated steel, conducted in the presence of Salmonella enterica , revealed a 60.4 ± 10.4% decrease in the corrosion rate compared to the bare steel. The prospect of implementing the developed coating technology on galvanized steel surfaces—including but not limited to grain storage silos as well as various food-related storage units and containers—presents an opportunity for significant progression within the multidisciplinary fields of food engineering, safety, and processing. [Display omitted] • Novel antifouling/anticorrosion coating was developed for galvanized steel. • Coating exhibited antifouling effect against pathogenic fungi Aspergillus niger. • With use of coating, adhesion of Salmonella and Listeria was reduced by >99.5%. • Coated surfaces significantly reduced the corrosion rate induced by microorganisms. • The developed coating is ideal for galvanized steel food-contact surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • Durable superhydrophobic nanodiamond based coating for stainless-steel. • Water contact angle of 156.3 ± 1.9° with 2.3 ± 0.5° contact angle hysteresis. • Surfaces characterized with SEM, AFM, and ATR-FTIR. • 2.3 ± 0.6 log 10 & 2.0 ± 0.9 log 10 reductions in E. coli & L. innocua , respectively. • Resisted fouling from contaminated Romaine lettuce leaves. Increasing concerns revolve around bacterial cross-contamination of leafy green vegetables via food-contact surfaces. Given that stainless-steel is among the commonly used food-contact surfaces, this study reports a coating strategy enhancing its hygiene and microbiological safety through an antifouling approach via superhydrophobicity. The developed method involves growing a nickel-nanodiamond nanocomposite film on 304 stainless-steel via electroplating and sequential functionalization of the outer surface layer with nonpolar organosilane molecules via polydopamine moieties. The resultant superhydrophobic stainless-steel surfaces had a static water contact angle of 156.3 ± 1.9° with only 2.3 ± 0.5° contact angle hysteresis. Application of the coating to stainless-steel was demonstrated to yield 2.3 ± 0.6 log 10 and 2.0 ± 0.9 log 10 reductions in the number of adherent gram-negative Escherichia coli O157:H7 and gram-positive Listeria innocua cells, respectively. These population reductions were shown to be statistically significant (α = 0.05). Coated stainless-steel also resisted fouling when contacted with contaminated romaine lettuce leaves and maintained significant non-wetting character when abraded with sand or contacted with high concentration surfactant solutions. The incorporation of superhydrophobic stainless-steel surfaces into food processing equipment used for washing and packaging leafy green vegetables has the potential to mitigate the transmission of pathogenic bacteria within food production facilities. [ABSTRACT FROM AUTHOR]

Abstract As a result of frequent outbreaks occurring due to poor hygiene and improper sanitation of processing environments, there has been an increasing demand for the development of food-contact surface materials that intrinsically inhibit and reduce likelihood of potential microbial adherence and biofilm formation. Herein, we report the synergistic utilization of surface nanotexturing and chemical modifications with nonpolar functional groups on aluminum surfaces to produce coatings having bacterial super-repellant and mud anti-fouling characteristics. Using these coatings, the attachment of Salmonella Typhimurium LT2 and Listeria innocua as pathogen surrogates was reduced more than 99.0%, compared to the bare aluminum surfaces. In addition, the coating strongly resisted the adhesion of mud, showing a 10-fold reduction in the area of mud adhesion upon submerging in mud solution. Moreover, this method is both versatile and scalable, involving inert and biocompatible building blocks. Overall, this study contributes to the field of food safety through the design and development of novel coatings for achieving improved food safety and hygiene. Highlights • Biocompatible silica-based superhydrophobically-modified aluminum surfaces were developed. • Attachment of Salmonella Typhimurium LT2 and Listeria innocua was reduced by >99.0%. • Superhydrophobically-modified aluminum surfaces exhibited excellent mud-repelling activity. • Bacterial anti-adhesion properties are attributed to weak intermolecular interactions. • The proposed surface modification method can be applied to metal food-contact surfaces. [ABSTRACT FROM AUTHOR]

Foodborne illness outbreaks caused by bacterial pathogens may take place on a large scale and result in millions of hospitalizations and thousands of deaths every year throughout the world. One key strategy for dealing with this global issue is the design of smart surfaces and coatings which inhibit and reduce bacterial attachment. This can mitigate contamination and cross-contamination during farm-to-table food processing, promoting food safety, and hygiene. Herein, we reported a durable superhydrophobic coating on aluminum surfaces fabricated by sequential deposition of ultrahard nanodiamond, self-assembly of l-3,4-dihydroxyphenylalanine (l -dopamine), and chemical modification with an organoflurosilane. This coating achieved static, advancing, and receding water contact angles of 159.0 ± 2.5°,154.0 ± 2.4°; and 153.7 ± 1.7°, respectively, representing water super-repellency with a low overall root mean square (rms) roughness of 173.5 ± 69.6 nm. In comparison to the bare, unmodified aluminum, the coated aluminum surfaces prevented the attachment of 99.5% of applied Escherichia coli O157:H7 (E.coli O157:H7) and 99.0% of Staphylococcus aureus (S. aureus) cells. In addition, due to the presence of nanodiamond building blocks, the coated surfaces demonstrated a high mechanical resistance against scratching and endured at least 10,000 shearing/rubbing cycles with a nylon surface. Overall, we anticipate that implementation of this coating could improve safety and hygiene of food-contact surfaces that require harsher mechanical operational conditions. • Development of biocompatible nanodiamond-based superhydrophobic coating on aluminum surfaces. • Attachment of Escherichia coli O157:H7 and Staphylococcus aureus was reduced by >99.0%. • Superhydrophobic aluminum surfaces exhibited excellent mechanical resistance against polymer scratching. • Bacterial antiadhesion properties are based on the minimized contact area and weak intermolecular interactions. • The proposed superhydrophobic coating can be applied on metal food-contact surfaces. [ABSTRACT FROM AUTHOR]