Purpose: The purpose of the current study was to evaluate the effectiveness of three non-thermal light technologies (NUV-Vis, Continuous UV and HILP) on their ability to inactivate Escherichia coli K12 and Listeria innocua.
Methods: Experiments were conducted using E. coli K12 (DSM 1607) and L. innocua (NCTC 11288). The suspensions containing both E. coli and L. innocua were assessed for susceptibility to three light technologies in a liquid matrix (MRD). A wide spectrum of dosages, varying between 0.18-106.2 J/cm2, was used for all the light treatments.
Results: The results of the present study show that the HIPL treatment inactivated both E. coli and L. innocua more rapidly and effectively than either continuous UV-C or NUV-vis treatments. With HILP at a distance of 2.5 cm from the lamp, E. coli and L. innocua populations were reduced by 3.07 and 3.77 log CFU/ml, respectively, after a 5 sec treatment time, and were shown to be below the limit of detection (< 0.22 log CFU/ml) following 30 sec exposure to HILP (106.2 J/cm2).
Significance: These data suggest that short treatment times for decontamination efficiency would be an important factor related to productivity in the food industry. The findings presented here suggest the expansion of the aforementioned light technologies on food decontamination. Thus, these alternative non-thermal disinfection light techniques could find potential application for decontamination in the food industry.