Using Photocatalyst Metal Oxides as Antimicrobial Surface Coatings to Ensure Food Safety—Opportunities and Challenges

Abstract

Cross-contamination of foods with pathogenic microorganisms such as bacteria, viruses, and parasites may occur at any point in the farm to fork continuum. Food contact and nonfood contact surfaces are the most frequent source of microbial cross-contamination. In the wake of new and emerging food safety challenges, including antibioticresistant human pathogens, conventional sanitation and disinfection practices may not be sufficient to ensure safe food processing, proper preparation, and also not be environmentally friendly. Nanotechnology-enabled novel food safety interventions have a great potential to mitigate the risk of microbial cross-contamination in the food chain. Especially engineered nanoparticles (ENPs) are increasingly finding novel applications as antimicrobial agents. Among various ENPs, photocatalyst metal oxides have shown great promise as effective nontargeted disinfectants over a wide range of microorganisms. The present review provides an overview of antimicrobial properties of various photocatalyst metal oxides and their potential applications as surface coatings. Further, this review discusses the most common approaches to developing antimicrobial coatings, methods to characterize, test, and evaluate antimicrobial efficacy as well as the physical stability of the coatings. Finally, regulations and challenges concerning the use of these novel photocatalytic antimicrobial coatings are also discussed.

Mo doped TiO2: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

“…Moreover, the photo-generated charge carriers could easily be trapped and localised on the TiO 2 surface by Mo 6+ and Mo 5+ ions to improve the photocatalytic activity. coatings [8,9]. The most commonly existing crystalline polymorphs of TiO 2 are anatase, rutile and brookite [10][11][12].…”

Antimicrobial Metal Nanomaterials: From Passive to Stimuli‐Activated Applications

“…Photocatalytic nanomaterials can be activated by light to produce free ROS, which have associated antimicrobial properties. [ 41,70,112,164–166 ] Typically these nanomaterials are made from semiconductor materials, which have a relatively small difference between the valence band and conduction band, known as the energy “bandgap.” [ 167 ] The valence band of an atom is the outer‐most orbital that electrons freely occupy when the material is in its ground state; meanwhile, the conduction band describes the higher energy orbitals into which electrons can freely transition when the material is in an excited state. When electrons are in the conduction band, they possess sufficient energy to move freely in the material, resulting in conductivity.…”

Antimicrobial Coatings for Food Contact Surfaces: Legal Framework, Mechanical Properties, and Potential Applications

“…However, in this case, the migration of the active agent occurs due to a failure, because the antimicrobial substance is expected to remain adhered to the FCS and to exert its action from the surface upon which it remains. The facile detachment of active coatings from their substrates and their low durability when subjected to complex environments are some of the main reasons for the scarcity of AMCs observed in commercial applications (Yemmireddy & Hung, 2017). Given this, surface adhesion has been a subject of multiple investigations (Bera, Rout, Udayabhanu, & Narayan, 2016;Karbay, Budakoglu, & Zayim, 2015;Lv et al, 2018).…”

“…In the second experiment, Hung and Yemmireddy (2015) quantified the wear of the AMC using an abrasive reciprocating apparatus that exerted force with sponges and brushes on coatings prepared with different types of binders. Later, Yemmireddy and Hung (2017) explored the effect of multiple washes and use cycles on HDPE cutting boards covered by TiO 2 nanoparticles. The cutting boards showed similar or decreased antimicrobial activity after repeated use (Yemmireddy & Hung, 2017).…”

“…Later, Yemmireddy and Hung (2017) explored the effect of multiple washes and use cycles on HDPE cutting boards covered by TiO 2 nanoparticles. The cutting boards showed similar or decreased antimicrobial activity after repeated use (Yemmireddy & Hung, 2017). These studies suggest that the reduction in the efficacy of AMCs over several use cycles is a challenge that still needs to be addressed.…”