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Table 1 Viability of biofilm-encased E. coli and L. monocytogenes (on lettuce or LDPE) after PUV treatment

From: Inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in biofilms by pulsed ultraviolet light

Microorganism PUV-treatment [time (s)/distance (cm)] Viable cell population (log RLU mL−1)
Lettuce LDPE
24 h 48 h 24 h 48 h
E. coli O157:H7 Control (no PUV) 4.50 ± 0.34 A 4.40 ± 0.29 A 4.53 ± 0.35 A 4.04 ± 0.30 A
10 s—4.5 cm 1.97 ± 0.22 C 2.35 ± 0.27 B 0.99 ± 0.17 B 1.34 ± 0.23 B
20 s—4.5 cm 1.22 ± 0.20 C 1.74 ± 0.24 C 0.62 ± 0.15 C 1.20 ± 0.20 B
10 s—8.8 cm 2.61 ± 0.31 B 2.65 ± 0.29 B 1.23 ± 0.24 B 1.65 ± 0.24 B
20 s—8.8 cm 1.62 ± 0.25 C 2.04 ± 0.26 B 0.90 ± 0.16 B 1.38 ± 0.13 B
L. monocytogenes Control (no PUV) 4.80 ± 0.35 A 4.70 ± 0.46 A 4.96 ± 0.32 A 4.71 ± 0.36 A
10 s—4.5 cm 3.39 ± 0.24 B 3.78 ± 0.37 B 1.17 ± 0.22 C 2.15 ± 0.31 B
20 s—4.5 cm 2.53 ± 0.22 C 2.88 ± 0.33 B 1.15 ± 0.20 C 1.88 ± 0.33 C
10 s—8.8 cm 3.90 ± 0.30 AB 4.10 ± 0.40 A 2.20 ± 0.32 B 2.80 ± 0.41 B
20 s—8.8 cm 2.83 ± 0.27 B 3.19 ± 0.36 B 1.67 ± 0.25 C 2.11 ± 0.36 B
  1. PUV-light treatment was performed under four different exposure conditions, i.e., different times (in s) and distances (in cm). Each treatment was replicated twice and assays were performed in triplicate. Values (mean ± SE) are given for each surface (lettuce or LDPE) and each incubation time (24 or 48 h post-inoculation), and different letters denote significant differences (P < 0.05).