Efficacy of Three Light Technologies for Reducing Microbial Populations in Liquid Suspensions

Abstract EN

The aim of the current study was to evaluate the effectiveness of three nonthermal light technologies (NUV-Vis, continuous UV, and HILP) on their ability to inactivate Escherichia coli K12 and Listeria innocua. E.

coli K12 was selected as a representative microorganism for the enterohaemorrhagic foodborne pathogen E.

coli O157:H7 and L.

innocua as a surrogate microorganism for the common foodborne pathogen Listeria monocytogenes, respectively.

The liquid matrix used for the disinfection experiments was a liquid matrix (MRD solution).

The results of the present study show that the HILP treatment inactivated both E.

coli and L.

innocua more rapidly and effectively than either continuous UV-C or NUV-vis treatment.

With HILP at 2.5 cm from the lamp, E.

coli and L.

innocua populations were reduced by 3.07 and 3.77 log10 CFU/mL, respectively, after a 5 sec treatment time, and were shown to be below the limit of detection (<0.22 log10 CFU/mL) following 30 sec exposure to HILP (106.2 J/cm2).

These studies demonstrate the bactericidal efficacy of alternative nonthermal light technologies and their potential as decontamination strategies in the food industry.