Sporicidal efficiency of an ultra-high irradiance (UHI) near UV/visible light treatment: An example of application to infected mandarins

Thery, Thibaut; Beney, Laurent; Grangeteau, Cédric; Dupont, Sébastien

doi:10.1016/j.foodcont.2022.109568

Cited by 4 publications

(1 citation statement)

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“…Likewise, Lang, et al [ 36 ] found that short-time treatments (below 10 min) with a UHI 405 nm LED induced >4.5 log reduction in S. cerevisiae counts inoculated in several food contact surface materials. A study by Thery et al [ 38 ] has shown the sporicidal efficiency of UHI blue LED treatments against spores of B. cereus , S. cerevisiae , and Penicillium spp., with reduction levels ranging from 0.8 to 4.2 log CFU/mL. In comparison, the antimicrobial effectiveness of UV-C light under dry conditions appears to be limited.…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of Ultra-High Irradiance Blue-Light-Emitting Diodes to Control Salmonella Contamination Adhered to Dry Stainless Steel Surfaces

Minor,

Sabillón

2024

Microorganisms

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Controlling Salmonella contamination in dry food processing environments represents a significant challenge due to their tolerance to desiccation stress and enhanced thermal resistance. Blue light is emerging as a safer alternative to UV irradiation for surface decontamination. In the present study, the antimicrobial efficacy of ultra-high irradiance (UHI) blue light, generated by light-emitting diodes (LEDs) at wavelengths of 405 nm (841.6 mW/cm2) and 460 nm (614.9 mW/cm2), was evaluated against a five-serovar cocktail of Salmonella enterica dry cells on clean and soiled stainless steel (SS) surfaces. Inoculated coupons were subjected to blue light irradiation treatments at equivalent energy doses ranging from 221 to 1106 J/cm2. Wheat flour was used as a model food soil system. To determine the bactericidal mechanisms of blue light, the intracellular concentration of reactive oxygen species (ROS) in Salmonella cells and the temperature changes on SS surfaces were also measured. The treatment energy dose had a significant effect on Salmonella inactivation levels. On clean SS surfaces, the reduction in Salmonella counts ranged from 0.8 to 7.4 log CFU/cm2, while, on soiled coupons, the inactivation levels varied from 1.2 to 4.2 log CFU/cm2. Blue LED treatments triggered a significant generation of ROS within Salmonella cells, as well as a substantial temperature increase in SS surfaces. However, in the presence of organic matter, the oxidative stress in Salmonella cells declined significantly, and treatments with higher energy doses (>700 J/cm2) were required to uphold the antimicrobial effectiveness observed on clean SS. The mechanism of the bactericidal effect of UHI blue LED treatments is likely to be a combination of photothermal and photochemical effects. These results indicate that LEDs emitting UHI blue light could represent a novel cost- and time-effective alternative for controlling microbial contamination in dry food processing environments.

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Section: Discussionmentioning

confidence: 99%