Effect of 450 nm Visible Blue Light from Light-Emitting Diode on Escherichia coli O157:H7 in Agar Gels: Optimizing the Lighting Array and Quantitative Microbial Exposure Assessment

Visible blue light emitting diodes (LED) have been studied to inactivate Escherichia coli (E. coli) O157:H7 in agar gels. The LED array was optimized attain uniform illumination, and the intensity distribution visualized through optical simulation. uniformity of assessed, evenly spaced showed best with a Petri factor 0.99. Microbial populations gels prepared without dye were analyzed after irradiation. Each segment different heights taken measure microbial reduction, results indicated that properties, such as opaqueness, played an important role reduction. gel maximum reduction <3.4 <2.1 log CFU/g, respectively. An exposure assessment for E. conducted based on assumption product illumination. probability risk (>5 CFU/g) existed mainly bottom layer sample, despite average contamination being <5 CFU/g. This study provides suitable approach designing photoinactivation process subsequent avoid risk.