TABLE 2.
Reductions in numbers of viable Escherichia coli O157:H7 cells on ham slice surfaces treated with UV, NIR, and NIR-UV
| Treatment time (s) | Log reduction (log10
n0 − log10
n) by treatment type and selective mediuma |
|||
|---|---|---|---|---|
| UV (SMAC) | NIR (SMAC) | NIR-UV |
||
| SMAC | SPRAB | |||
| 0 | 0.00 ± 0.00A | 0.00 ± 0.00A | 0.00 ± 0.00Aa | 0.00 ± 0.00Aa |
| 10 | 1.22 ± 0.27B | 0.06 ± 0.07A | 1.57 ± 0.33Ba | 1.49 ± 0.01Ba |
| 20 | 1.24 ± 0.26B | 0.11 ± 0.07A | 1.88 ± 0.24BCa | 1.54 ± 0.02Ba |
| 30 | 1.29 ± 0.22B | 0.21 ± 0.11A | 2.00 ± 0.38BCDa | 1.62 ± 0.08BCa |
| 40 | 1.43 ± 0.23B | 0.25 ± 0.11A | 2.14 ± 0.30CDa | 1.81 ± 0.34BCa |
| 50 | 1.46 ± 0.21B | 0.69 ± 0.27B | 2.46 ± 0.19DEa | 1.96 ± 0.25Ca |
| 60 | 1.50 ± 0.24B | 1.05 ± 0.23C | 2.68 ± 0.16Ea | 2.46 ± 0.30Da |
| 70b | 1.52 ± 0.15B | 1.46 ± 0.09D | 3.62 ± 0.26Fa | 3.23 ± 0.23Ea |
a
The values are means ± standard deviations from three replications. Means with the same uppercase letter in the same column are not significantly different (P > 0.05). Within the NIR-UV columns, values in the same row followed by the same lowercase letter are not significantly different (P > 0.05). SMAC, sorbitol MacConkey agar; SPRAB, phenol red agar base with 1% sorbitol; n0, initial population; n, population after treatment.
b
A statistically significant (P < 0.05) difference between the sum of NIR and UV inactivation and inactivation achieved with combination treatment was observed.