Inactivation ofCampylobacter jejuniby Exposure to High-Intensity 405-nm Visible Light

Abstract

Although considerable research has been carried out on a range of environmental factors that impact on the survival of Campylobacter jejuni, there is limited information on the effects of violet/blue light on this pathogen. This investigation was carried out to determine the effects of high-intensity 405-nm light on C. jejuni and to compare this with the effects on two other important Gram-negative enteric pathogens, Salmonella enteritidis and Escherichia coli O157:H7. High-intensity 405-nm light generated from an array of 405-nm light-emitting diodes was used to inactivate the test bacteria. The results demonstrated that while all three tested species were susceptible to 405-nm light inactivation, C. jejuni was by far the most sensitive organism, requiring a total dose of 18 J cm⁻² of 405-nm light to achieve a 5-log₁₀ reduction. This study has established that C. jejuni is particularly susceptible to violet/blue light at a wavelength of 405 nm. This finding, coupled with the safety-in-use advantages of this visible (non-ultraviolet wavelength) light, suggests that high-intensity 405-nm light may have applications for control of C. jejuni contamination levels in situations where this type of illumination can be effectively applied.

High‐Intensity 405 nm Light Inactivation of Listeria monocytogenes

“…sonnei to 405 nm light also demonstrated significant bacterial inactivation, with the inactivation kinetics of all the organisms investigated in this study showing a similar sigmoidal shape to those from previous studies on the bactericidal effect of 405 nm light (12,13,18). Treatment of L. monocytogenes and the other Listeria species using the 405 nm LED array resulted in similar inactivation kinetics, suggesting that bacteria within the same genus may undergo very similar inactivation reactions.…”

Inactivation by 405 ± 5 nm light emitting diode on Escherichia coli O157:H7, Salmonella Typhimurium, and Shigella sonnei under refrigerated condition might be due to the loss of membrane integrity

“…These differences in the effectiveness of 405 nm LED illumination might be due to the different experimental design such as the distance between LED and bacterial suspension, total volume and depth of bacterial suspension, initial population and set temperature Murdoch et al, 2010). In particular, the previous studies used magnetic stirring plate to agitate bacterial suspension during the illumination, probably maximizing its antibacterial effect Murdoch et al, 2010). However, the bacterial suspension was not agitated during illumination in the present study to simulate a food matrix.…”

“…Another study carried by Murdoch, Maclean, Endarko, MacGregor, and Anderson (2012) with 405 nm LED at the irradiance of 10 mW/cm 2 demonstrated that 5-log reductions of S. sonnei and E. coli O157:H7 were achieved at 180 and 288 J/cm 2 (5 and 8 h), respectively. These differences in the effectiveness of 405 nm LED illumination might be due to the different experimental design such as the distance between LED and bacterial suspension, total volume and depth of bacterial suspension, initial population and set temperature Murdoch et al, 2010). In particular, the previous studies used magnetic stirring plate to agitate bacterial suspension during the illumination, probably maximizing its antibacterial effect Murdoch et al, 2010).…”

“…Guffey and Wilborn (2006) reported that the populations of Pseudmonas aeruginosa and Shigella aureus after 405 nm LED illumination were reduced by 95 and 88%, respectively. Similarly, the study conducted by Murdoch et al (2010) has shown that Campylobacter jejuni and Salmonella Enteritidis were inactivated by 405 nm LED illumination without any exogenous photosensitizer. Based on these studies, LED technology has recently received increasing attention in its potential as light therapy for medical purposes, perhaps preventing antibiotic abuse (Maclean et al, 2009).…”

“…However, UV light leads to decolourization in certain products at high dose as well as has harmful effects on the skin tissue and eyes of the operator, resulting in the limitation of UV light as a preservation technology in food industry (Maclean, MacGregor, Anderson, & Woolsey, 2009;Murdoch, Maclean, MacGregor, & Anderson, 2010). To overcome these shortcomings of UV light, light emitting diodes (LED) of visible wavelengths have been investigated as an alternative.…”