Table 4. Bactericidal efficacies of the treatment solutions toward E. coli on carriers at room temperature.
| Solution | Type of carrier | dW2 Control log10 CFU/ml | Bacterial titer (log10 CFU/ml) at different contact times | |||
|---|---|---|---|---|---|---|
| 3 min | 30 sec | 1 min | 3 min | |||
| FdCa(OH)2a) | Rubber | 6.82 ± 0.20d) | NTe) | 4.24 ± 0.32 | 2.76 ± 0.16 | |
| QACx500b) | 4.84 ± 0.12 | 3.15 ± 0.08* | ≤2.60 ± 0.00 | |||
| Mix500c) | 3.17 ± 0.30* | ≤2.60 ± 0.00 | NT | |||
| FdCa(OH)2 | Steel | 7.24 ± 0.22 | NT | 4.80 ± 0.36 | ≤2.60 ± 0.00 | |
| QACx500 | 4.55 ± 0.20 | 3.31 ± 0.38* | ≤2.60 ± 0.00 | |||
| Mix500 | 3.48 ± 0.25* | ≤2.60 ± 0.00 | NT | |||
| FdCa(OH)2 | Plastic | 7.37 ± 0.20 | NT | 4.76 ± 0.40 | ≤2.60 ± 0.00 | |
| QACx500 | 5.06 ± 0.11 | 3.58 ± 0.53* | ≤2.60 ± 0.00 | |||
| Mix500 | 3.85 ± 0.52* | ≤2.60 ± 0.00 | NT | |||
a) Food additive grade calcium hydroxide powder (200 mg) was prepared in 100 ml of redistilled water (FdCa(OH)2). b) A quaternary ammonium compound (QAC) diluted by 1:500 in redistilled water (QACx500). c) FdCa(OH)2 powder (200 mg) was prepared in 100 ml of QACx500 (Mix500). d) Bacterial titer (log10 CFU/ml). e) Not tested. *Single asterisk indicates effective bacterial reduction (≥3 log10 CFU/ml). Bacterial titer ≤2.6 log10 CFU/ml indicates bacterial reduction to the undetectable level. Both effective and undetectable level bacterial reductions are significantly different (P<0.05) from dW2 control titer.