TABLE 3.

Log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes on sliced cheese after treatment with UV-LED PCBs at four different wavelengths

Organism and wavelength (nm)	Mean log reductiona (log10 CFU/g) ± SD at indicated dose
	1 mJ/cm2		2 mJ/cm2		3 mJ/cm2
E. coli O157:H7	SMAC	SPRAB	SMAC	SPRAB	SMAC	SPRAB
266	3.50 ± 0.57 Aa	3.21 ± 0.22 Aa	4.09 ± 0.46 Aa	3.43 ± 0.30 Aa	4.88 ± 0.18 Aa	4.49 ± 0.09 Ab
270	2.83 ± 0.43 Aa	3.09 ± 0.72 Aa	3.99 ± 0.10 Aa	3.73 ± 0.10 Ab	4.81 ± 0.10 Aa	4.14 ± 0.72 ABa
275	2.78 ± 0.36 Aa	2.74 ± 0.42 Aa	3.79 ± 0.50 Aa	3.39 ± 0.43 Aa	4.31 ± 0.31 Ba	4.13 ± 0.28 ABa
279	2.80 ± 0.53 Aa	2.86 ± 0.73 Aa	3.46 ± 0.51 Aa	3.38 ± 0.40 Aa	4.04 ± 0.33 Ba	3.64 ± 0.17 Ba
S. Typhimurium	XLD	OV-XLD	XLD	OV-XLD	XLD	OV-XLD
266	3.10 ± 0.24 Aa	3.13 ± 0.25 Aa	3.93 ± 0.68 Aa	3.42 ± 0.46 Aa	4.72 ± 0.02 Aa	4.50 ± 0.37 Aa
270	2.82 ± 0.33 Aa	3.08 ± 0.47 Aa	3.70 ± 0.12 Aa	3.43 ± 0.41 Aa	4.73 ± 0.05 Aa	4.37 ± 0.39 Aa
275	2.83 ± 0.31 Aa	2.91 ± 0.20 Aa	3.24 ± 0.36 Aa	3.35 ± 0.28 Aa	4.24 ± 0.26 Ba	4.04 ± 0.22 Aa
279	2.73 ± 0.38 Aa	2.93 ± 0.37 Aa	3.17 ± 0.39 Aa	2.94 ± 0.61 Aa	3.91 ± 0.05 Ca	3.96 ± 0.28 Aa
L. monocytogenes	OAB	OV-OAB	OAB	OV-OAB	OAB	OV-OAB
266	3.09 ± 0.26 Aa	2.55 ± 0.22 Ab	3.10 ± 0.10 Aa	3.03 ± 0.43 Aa	3.52 ± 0.05 ABa	3.32 ± 0.75 Aa
270	2.89 ± 0.19 Aa	2.66 ± 0.62 Aa	2.97 ± 0.44 Aa	2.73 ± 0.21 Aa	3.94 ± 0.55 Aa	3.06 ± 0.25 ABa
275	2.54 ± 0.41 Aa	2.04 ± 0.11 ABa	2.72 ± 0.34 ABa	2.43 ± 0.30 Aa	3.31 ± 0.22 Ba	2.57 ± 0.18 ABb
279	2.33 ± 0.65 Aa	1.72 ± 0.24 Ba	2.37 ± 0.17 Ba	2.07 ± 0.84 Aa	3.24 ± 0.08 Ba	2.27 ± 0.37 Bb

^aData represent means from three replications. Values followed by the same uppercase letters within columns and lowercase letters within rows for each dose are not significantly different. Media: SMAC, sorbitol MacConkey agar; SPRAB, phenol red agar base with 1% sorbitol; XLD, xylose lysine desoxycholate agar; OV-XLD, overlay XLD agar on TSA; OAB; Oxford agar base with antimicrobial supplement; OV-OAB, overlay OAB agar on TSA.