title: Inactivation of foodborne pathogenic and spoilage micro-organisms using ultraviolet-A light in combination with ferulic acid.
abstract: The low energy of UV-A (315-400 nm) is insufficient for disinfection. To improve UV-A disinfection technology, we evaluated the effect of ferulic acid (FA) addition on disinfection by UV-A light-emitting diode (LED) (350-385 nm) against various food spoilers and pathogens (seven bacteria and four fungi species). Photoantimicrobial assays were performed at FA concentrations below the MIC. The MIC of the isomerized FA, consisting of 93% cis-form and 7% trans-form, was very similar to that of the commercially available FA (trans-form). Irradiation with UV-A (1·0 J cm-2) in the presence of 100 mg l-1FA resulted in enhanced reducing of all of the tested bacterial strains. A combination of UV-A (10 J cm-2) and 1000 mg l-1FA resulted in enhanced reducing of Saccharomyces cerevisiae and one of the tested filamentous fungi. These results demonstrated that the combination of a short-term application of UV-A and FA at a low concentration yielded synergistic enhancement of antimicrobial activity, especially against bacteria.
  
  
  CONCLUSIONS
  Microbial contamination is one of the most serious problems for foods, fruit and sugar thick juices. UV light is suitable for the nonthermal decontamination of food products by inactivating the contaminating micro-organisms. However, UV-A exposure is insufficient for disinfection. This study demonstrates that the combination of UV-A LED light (350-385 nm), which is not hazardous to human eyes and skin, and ferulic acid (FA), a known phytochemical and food additive, provides synergistic antimicrobial activity against foodborne pathogenic and spoilage micro-organisms. Therefore, FA addition to UV-A light treatment may be useful for improvement of UV-A disinfection technology to prevent food deterioration.
authors.affiliation: Department of Bioresource Chemistry and Technology, Graduate School of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Shirai
authors.affiliation: Department of Biological Science and Technology, Faculty of Engineering, Tokushima University, Tokushima, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Bioresource Chemistry and Technology, Graduate School of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Matsuki
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000528:radiation effects*; D003373:Coumaric Acids / Q000494:pharmacology*; D003666:Decontamination; D004203:Disinfection / Q000379:methods*; D005506:Food Contamination; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology / Q000517:prevention & control*; D005658:Fungi / Q000187:drug effects* / Q000528:radiation effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D003373:Coumaric Acids; C004999:ferulic acid
keywords: UV-A; ferulic acid; food spoilers; foodborne pathogens; photoantimicrobial activity