Non-thermal inactivation effects of metal oxide nanoparticles–graphene composite films on foodborne pathogens to reduce proliferation

Emergence of antibiotic-resistant foodborne pathogens poses a significant threat to global public health. There is an urgent demand for next-generation antibacterial materials to effectively control the proliferation of pathogenic bacteria. This study fabricated graphene films with bactericidal properties via an approach that entailed the laser synthesis of high dense and uniform metal oxide nanoparticles, viz., titanium dioxide (TiO₂), copper (II) oxide (CuO), and iron (II) oxide (Fe₃O₄) nanoparticles, directly onto ultraviolet laser-induced graphene (UV-LIG) surfaces. Bacterial treatment on UV-LIG decorated with dense and uniform TiO₂ nanospheres significantly reduced the counts of Bacillus cereus, Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7, and Staphylococcus aureus to below the detection limit (log CFU/mL), achieving above 99.999 kill rate. TiO₂/UV-LIG films limited cell proliferation rates of pathogens B. cereus to 1.3 % and S. Typhimurium to 2.1 % after 24-h. These results demonstrate that utilizing highly dense and uniform TiO₂ nanospheres on UV-LIG composite films is a promising strategy for combating foodborne pathogens.