期刊
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY
卷 153, 期 -, 页码 33-39出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jphotobiol.2015.08.032
关键词
405 nm light emitting diode; Photodynamic inactivation; Gram-positive foodborne pathogens; Membrane permeability; DNA damage
资金
- A*STAR Nutrition and Food Science grant [SERC 112-177-0035]
This study investigated the antibacterial effect of 405 +/- 5 nm light emitting diode (LED) on Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus, and examined its antibacterial mechanism by determining the bacterial membrane and DNA damages. A 405 +/- 5 nm LED illuminated the Gram-positive pathogens until 486 J/cm(2) at 4 degrees C. Weibull model was used to calculate reliable life (t(R)) to compare bacterial sensitivities to LED illumination. The membrane damage was determined by NaCl and LIVE/DEAD (R) assay, while comet assay and DNA ladder analysis were conducted to determine DNA degradation. The illumination resulted in 1.9, 2.1, and 1.0 log reductions for B. cereus, L. monocytogenes, and S. aureus at 486 J/cm(2), respectively. The comparison of tit values revealed that L. monocytogenes was identified as the most susceptible strain to LED illumination. The percentage of the bacterial sensitivity to NaCl remarkably increased in LED-illuminated cells compared to non-illuminated cells. Moreover, loss of membrane integrity was confirmed for LED-illuminated cells by LIVE/DEAD (R) assay, whereas no DNA breakage was indicated by comet assay and DNA ladder analysis. Thus, these findings suggest that the antibacterial effect of 405 +/- 5 nm LED illumination on these pathogens might be due to physical damage to bacterial membrane rather than DNA degradation. (C) 2015 Elsevier B.V. All rights reserved.
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