Molybdenum doped titanium dioxide photocatalytic coatings for use as hygienic sufaces: The effect of soiling on antimicrobial activity

Titanium dioxide (TiO₂) surfaces doped with molybdenum (Mo) were investigated to determine if their photocatalytic ability could enhance process hygiene in the brewery industry. Doping TiO₂ with Mo showed a 5-log reduction in bacterial counts within 4 to 24 h and a 1-log reduction in yeast numbers within 72 h. The presence of a dilute brewery soil on the surface did not interfere with antimicrobial activity. The TiO₂–Mo surface was also active in the dark, showing a 5-log reduction in bacteria within 4 to 24 h and a 1-log reduction in yeast numbers within 72 h, suggesting it could have a novel dual function, being antimicrobial and photocatalytic. The study suggests the TiO₂–Mo coating could act as a secondary barrier in helping prevent the build-up of microbial contamination on surfaces within the brewery industry, in particular in between cleaning/disinfection regimes during long production runs.