TABLE 1.
Reductions of three pathogens on culture media after treatment with continuous or pulsed UVC-LED irradiation at different frequencies
| Microorganism | Reduction (log CFU/ml)a |
|||||
|---|---|---|---|---|---|---|
| Continuous |
1,000 Hz |
20 Hz |
||||
| Selective | Nonselective | Selective | Nonselective | Selective | Nonselective | |
| E. coli O157:H7 | 4.50 ± 0.37 A | 4.94 ± 0.10 A | 4.46 ± 0.16 A | 5.04 ± 0.04 B | 5.17 ± 0.19 A | 5.10 ± 0.05 A |
| S. Typhimurium | 2.94 ± 0.05 A | 2.84 ± 0.10 A | 3.43 ± 0.28 A | 2.65 ± 0.43 A | 4.10 ± 0.06 A | 3.19 ± 0.37 B |
| L. monocytogenes | 2.35 ± 0.30 A | 1.78 ± 0.10 B | 2.47 ± 0.48 A | 1.77 ± 0.13 A | 3.01 ± 0.59 A | 2.04 ± 0.13 A |
a
The highest dosages were applied (2 mJ/cm2 for E. coli O157:H7 and 5 mJ/cm2 for S. Typhimurium and L. monocytogenes). Data represent means ± standard deviations from three replications. Values followed by the same uppercase letters within rows for each treatment type are not significantly different.