Photocatalytic TiO2 coating of plastic cutting board to prevent microbial cross-contamination

Kitchen cutting boards are one common source of microbial cross-contamination in foods. In this study, a method was developed to create an antimicrobial coating on HDPE cutting board using UV-activated TiO2 nanoparticles (NPs). The antimicrobial efficacy of the developed coatings was tested against E. coli O157: H7 for 3 h at 0.5 ± 0.05 mW/cm2 UVA light intensity. In addition, the effect of NP loading (0.0125, 0.0625, and 0.125 mg/cm2), and surface treatment of coatings by oxygen plasma for 1-15 min on the bactericidal efficacy was investigated. Further, the bactericidal efficacy of the TiO2 coated cutting board on repeated use (i.e. 1, 2, 3 and 5 times) was also evaluated. The results showed that by increasing the NP loading from 0 to 0.125 mg/cm2 has increased the log reduction from 0.37 to 1.18 CFU/cm2. However, no significant difference (P > 0.05) in the reduction was observed between NP loadings at 0.0625 and 0.125 mg/cm2. Oxygen plasma treatment of the coated surfaces for 5-15 min significantly increased (P ≤ 0.05) the log reduction compared to control sample without plasma treatment. Under the tested conditions, TiO2 coating with 0.0625 mg/cm2 NP loading followed by oxygen plasma treatment for 5 min was found to achieve the greatest reduction up to 2.67 log CFU/cm2. Also, the coated-surfaces were found to retain the original bactericidal property even after up to 5 times washing treatment. The developed TiO2 coating on cutting board showed promise to mitigate the risk of microbial cross-contamination by providing a stable antimicrobial activity for extended use. Plasma treatment further enhanced the bactericidal property of the developed coatings without affecting physical stability.