title: Inactivation of pathogenic bacteria inoculated onto a Bacto™ agar model surface using TiO2-UVC photocatalysis, UVC and chlorine treatments.
abstract: OBJECTIVE
  The aim of this study was to study inactivation of different pathogenic bacteria on agar model surface using TiO2-UV photocatalysis (TUVP).
  
  
  RESULTS
  A unified food surface model was simulated using Bacto(™) agar, a routinely used microbial medium. The foodborne pathogenic bacteria Escherichia coli K12 (as a surrogate for E. coli O157:H7), Salmonella Typhimurium, Staphylococcus aureus and Listeria monocytogenes were inoculated onto the agar surface, followed by investigation of TUVP-assisted inactivation and morphological changes in bacterial cells. The TUVP process showed higher bacterial inactivation, particularly for Gram-negative bacteria, than UVC alone and a control (dark reaction). A TUVP treatment of 17·2 mW cm(-2) (30% lower than the UVC light intensity) reduced the microbial load on the agar surface by 4·5-6·0 log CFU cm(-2). UVC treatment of 23·7 mW cm(-2) caused 3·0-5·3 log CFU cm(-2) reduction.
  
  
  CONCLUSIONS
  The use of agar model surface is effective for investigation of bacterial disinfection and TUVP is a promising nonthermal technique.
  
  
  CONCLUSIONS
  The results showing effects of photocatalysis and other treatments for inactivation of bacterial pathogens on model surface can be useful for applying such processes for disinfection of fruit, vegetables and other similar surfaces.
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Yoo
authors.affiliation: Department of Food Science and Nutrition, King Saud University, Riyadh, Saudi Arabia.
authors.forename: K
authors.initials: K
authors.lastname: Ghafoor
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: Y W
authors.initials: YW
authors.lastname: Sun
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: J U
authors.initials: JU
authors.lastname: Kim
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: K
authors.initials: K
authors.lastname: Yang
authors.affiliation: Department of Food Science and Technology, Chung-Ang University, Anseong, Korea.
authors.forename: D-U
authors.initials: DU
authors.lastname: Lee
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: H M
authors.initials: HM
authors.lastname: Shahbaz
authors.affiliation: Department of Biotechnology, Yonsei University, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Park
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects*; D002713:Chlorine / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods*; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D005638:Fruit / Q000382:microbiology; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: C009495:titanium dioxide; D002713:Chlorine; D014025:Titanium
keywords: TiO2-UV photocatalysis; UVC treatment; agar model surface; cell morphology; pathogenic bacteria