Watanabe, Takashi Tokushima University
The low energy of UV-A (315–400 nm) is insufficient for disinfection. To improve UV-A disinfection technology, the effect of ferulic acid (FA) addition on inactivation by UV-A light-emitting diode (LED) light (350–385 nm) was evaluated in the eliminating of suspensions of various food spoilers and pathogens (seven bacteria and four fungi). 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-236 ) in the presence of 100 mg l-1 37 FA resulted in enhanced reducing of all of the tested bacterial strains. A combination of UV-A (10 J cm-2) and 1000 mg l-1 38 FA 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.
Letters in Applied Microbiology
© 2016 The Society for Applied Microbiology