CFU/g O157:H7 K-12 Conc (ng/μl) Ratio of A260/280 Conc (ng/μl) Ratio of A260/280 Noncell control 7.17 ± 4.62 1.44 ± 0.24 2.03 ± 0.28 1.75 ± 0.19 1×101 Living cells 2.73 ± 1.15 1.32 ± 0.34 10.4 ± 4.58 0.89 ± 0.31 1×102 Living cells 3.50 ± 0.46 1.49 ± 0.08 2.26 ± 0.90 1.51 ± 0.09 1×103 Living cells 3.30 ± 0.53 1.64 ± 0.11 7.78 ± 3.76 1.14 ± 0.04 1×104 Living cells 3.27 ± 1.33 1.80 ± 0.75 3.42 ± 0.14 1.51 ± 0.13 1×106 Living cells ND* ND 8.82 ± 0.11 1.82 ± 0.04 1×101 dead cells 2.47 ± 0.04 1.26 ± 0.04 15.4 ± 3.79 1.21 ± 0.46 1×102 dead cells 2.21 ± 0.83 1.20 ± 0.03 2.57 ± 0.24 1.65 ± 0.02 1×103 dead cells 3.07 ± 0.31 1.24 ± 0.18 6.74 ± 0.54 1.18 ± 0.11 1×104 dead cells 2.97 ± 0.67 1.54 ± 0.15 3.16 ± 0.94 1.43 ± 0.03 1×106 dead cells ND ND 4.57 ± 1.21 1.65 ± 0.10 *because they are not determined

Table 1: Concentration and A260/280 ratio of total RNA extracted from food samples inoculated with live and dead cells.