Performance and mechanism of standard nano-TiO2 (P-25) in photocatalytic disinfection of foodborne microorganisms – Salmonella typhimurium and Listeria monocytogenes |
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| Affiliation: | 1. College of Food Science and Technology, Nanjing Agricultural University, 1st Tongwei Road, Weigang, Nanjing, Jiangsu 210095, PR China;2. Quality and Safety Assessment Research Unit, 950 College Station Road, Athens, GA 30605, USA;1. School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, China;2. Academy of Contemporary Food Engineering, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, China;3. Engineering and Technological Research Centre of Guangdong Province on Intelligent Sensing and Process Control of Cold Chain Foods, & Guangdong Province Engineering Laboratory for Intelligent Cold Chain Logistics Equipment for Agricultural Products, Guangzhou Higher Education Mega Centre, Guangzhou 510006, China;4. Food Refrigeration and Computerized Food Technology (FRCFT), Agriculture and Food Science Centre, University College Dublin, National University of Ireland, Belfield, Dublin 4, Ireland;1. Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Manuel Nava No. 6, San Luis Potosí, S.L.P. C.P. 78290, México;2. Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, Departamento de Ecomateriales y Energía, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66455, México;1. Department of Electronic Engineering, Laboratory of Micro/Nano-Optoelectronics, Xiamen University, Xiamen, Fujian, 361005, China;2. Department of Electronic Science, Fujian Engineering Research Center for Solid-State Lighting, Xiamen University, Xiamen, 361005, China;3. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, China |
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| Abstract: | Under UV light, nano-TiO2 is effective in photocatalytic disinfection. In this paper, we studied the disinfection effects of nano-TiO2 on the two typical food-borne microorganisms, Gram-negative bacterium-Salmonella typhimurium and Gram-positive bacterium-Listeria monocytogenes, in meat products. Results show that nano-TiO2 had a strong disinfecting activity against both Gram-negative and Gram-positive pathogens in a suspension under UV light. L. monocytogenes was more resistant to nano-TiO2 treatment than Salmonella under UV light. Nano-TiO2 concentrations and initial bacteria populations had significant influence on the photocatalytic disinfection effectiveness against S. typhimurium. The optimum concentration (1.0 g/L) was between 0.2 g/L and 1.5 g/L. Increasing S. typhimurium population from 104 to 107 CFU/mL resulted in reduced photocatalytic disinfecting effectiveness by nano-TiO2. Electron microscope images revealed that nano-TiO2 photocatalytic disinfection starts with damaging the cell walls of bacteria. With serious destructions of cell walls, cell components released or defused out of cell from the damaged areas, and finally the cells completely lost their integrity and dissolved. These results demonstrate that nano-TiO2 is very effective against pathogens that can grow well on meat products and the effectiveness can be significantly influenced by nano-TiO2 contents and pathogen populations. The findings by these experiments provide the essential information for further developing a nano-metal-based, antimicrobial packaging system to improve safety of meat products. |
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| Keywords: | Nano-metal oxides Photocatalytic disinfection |
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