Table 5. Bactericidal efficacies of the treatment solutions toward E. coli on carriers at 2°C.
| 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 | 6.63 ± 0.18d) | NTe) | 5.29 ± 0.33 | 3.32 ± 0.15* |
| QACx500b) | 5.13 ± 0.08 | 3.92 ± 0.05 | 3.09 ± 0.29* | ||
| Mix500c) | 4.49 ± 0.25 | 3.23 ± 0.32* | ≤2.60 ± 0.00 | ||
| FdCa(OH)2 | Steel | 7.29 ± 0.13 | NT | 5.55 ± 0.22 | 3.32 ± 0.36* |
| QACx500 | 5.28 ± 0.29 | 4.37 ± 0.24 | 2.88 ± 0.28* | ||
| Mix500 | 4.78 ± 0.11 | 3.88 ± 0.10* | ≤2.60 ± 0.00 | ||
| FdCa(OH)2 | Plastic | 6.92 ± 0.28 | NT | 4.69 ± 0.31 | 3.53 ± 0.25* |
| QACx500 | 4.97 ± 0.20 | 4.10 ± 0.14 | 3.04 ± 0.24* | ||
| Mix500 | 4.16 ± 0.25 | 3.20 ± 0.39* | ≤2.60 ± 0.00 | ||
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.