Table 4.
Risk comparison with different hand washing practices.
| a. Estimated risk from different exposure protocols calculated using three dose models. | ||||||||||||
| Risk with Recommended Dose Response Model | Risk with High Infectious Dose Model | Risk with Low Infectious Dose Model | ||||||||||
| Median (5%, 95%) | Median (5%, 95%) | Median (5%, 95%) | ||||||||||
| No Washing | Control Bar | Antimicrobial #1 | Antimicrobial #2 | No Washing | Control Bar | Antimicrobial #1 | Antimicrobial #2 | No Washing | Control Bar | Antimicrobial #1 | Antimicrobial #2 | |
| Transfer from Meat Preparation Surfaces | ||||||||||||
| Cutting board-to-meat (high dose) |
1.20 × 10−2 | 2.20 × 10−3 | 3.80 × 10−4 | 5.70 × 10−4 | 8.70 × 10−5 | 1.60 × 10−5 | 2.70 × 10−6 | 4.10 × 10−6 | 2.10 × 10−2 | 3.90 × 10−3 | 6.70 × 10−4 | 1.00 × 10−3 |
| (0.0 × 100, 2.2 × 10−1) | (0.0 × 100, 8.8 × 10−2) | (0.0 × 100, 2.2 × 10−2) | (0.0 × 100, 3.1 × 10−2) | (0.0 × 100, 4.3 × 10−3) | (0.0 × 100, 8.8 × 10−4) | (0.0 × 100, 1.7 × 10−4) | (0.0 × 100, 2.5 × 10−4) | (0.0 × 100, 4.0 × 10−1) | (0.0 × 100, 1.6 × 10−1) | (0.0 × 100, 4.0 × 10−2) | (0.0 × 100, 5.6 × 10−2) | |
| Cutting board-to-meat (low dose) |
1.60 × 10−4 | 2.70 × 10−5 | 4.80 × 10−6 | 7.20 × 10−6 | 1.10 × 10−6 | 1.90 × 10−7 | 3.40 × 10−8 | 5.10 × 10−8 | 2.70 × 10−4 | 4.80 × 10−5 | 8.50 × 10−6 | 1.30 × 10−5 |
| (3.6 × 10−6, 6.1 × 10−3) | (4.0 × 10−7, 1.3 × 10−3) | (1.8 × 10−9, 2.6 × 10−4) | (0.0 × 100, 3.8 × 10−4) | (2.6 × 10−8, 4.4 × 10−5) | (2.8 × 10−9, 9.6 × 10−6) | (1.3 × 10−11, 1.8 × 10−6) | (0.0 × 100, 2.7 × 10−6) | (6.5 × 10−6, 1.1 × 10−2) | (7.1 × 10−7, 2.4 × 10−3) | (3.2 × 10−9, 4.5 × 10−4) | (0.0 × 100, 6.8 × 10−4) | |
| Knife-to-meat (high dose) |
3.20 × 10−2 | 6.50 × 10−3 | 1.10 × 10−3 | 1.70 × 10−3 | 2.60 × 10−4 | 4.70 × 10−5 | 7.90 × 10−6 | 1.20 × 10−5 | 5.80 × 10−2 | 1.20 × 10−2 | 2.00 × 10−3 | 3.00 × 10−3 |
| (9.2 × 10−4, 3.1 × 10−1) | (9.9 × 10−5, 1.6 × 10−1) | (1.8 × 10−7, 4.8 × 10−2) | (0.0 × 100, 6.9 × 10−2) | (6.5 × 10−6, 1.0 × 10−2) | (7.0 × 10−7, 2.2 × 10−3) | (1.3 × 10−9, 4.1 × 10−4) | (0.0 × 100, 6.4 × 10−4) | (1.6 × 10−3, 5.4 × 10−1) | (1.8 × 10−4, 2.9 × 10−1) | (3.3 × 10−7, 8.6 × 10−2) | (0.0 × 100, 1.3 × 10−1) | |
| Knife-to-meat (low dose) |
4.70 × 10−4 | 8.40 × 10−5 | 1.50 × 10−5 | 2.20 × 10−5 | 3.40 × 10−6 | 5.90 × 10−7 | 1.00 × 10−7 | 1.60 × 10−7 | 8.40 × 10−4 | 1.50 × 10−4 | 2.60 × 10−5 | 3.90 × 10−5 |
| (5.5 × 10−6, 2.6 × 10−2) | (4.9 × 10−7, 5.6 × 10−3) | (0.0 × 100, 1.1 × 10−3) | (0.0 × 100, 1.6 × 10−3) | (3.9 × 10−8, 2.1 × 10−4) | (3.5 × 10−9, 4.1 × 10−5) | (0.0 × 100, 7.9 × 10−6) | (0.0 × 100, 1.1 × 10−5) | (9.7 × 10−6, 4.7 × 10−2) | (8.7 × 10−7, 1.0 × 10−2) | (0.0 × 100, 2.0 × 10−3) | (0.0 × 100, 2.8 × 10−3) | |
| Meat-to-cutting board (high dose) |
1.90 × 10−1 | 6.00 × 10−2 | 1.40 × 10−2 | 2.00 × 10−2 | 3.00 × 10−3 | 5.40 × 10−4 | 1.00 × 10−4 | 1.50 × 10−4 | 3.40 × 10−1 | 1.10 × 10−1 | 2.40 × 10−2 | 3.50 × 10−2 |
| (3.9 × 10−2, 4.0 × 10−1) | (5.2 × 10−3, 2.6 × 10−1) | (2.2 × 10−4, 1.1 × 10−1) | (0.0 × 100, 1.4 × 10−1) | (3.2 × 10−4, 2.7 × 10−2) | (3.5 × 10−5, 6.3 × 10−3) | (1.6 × 10−6, 1.3 × 10−3) | (0.0 × 100, 1.8 × 10−3) | (7.1 × 10−2, 6.8 × 10−1) | (9.2 × 10−3, 4.7 × 10−1) | (4.0 × 10−4, 2.1 × 10−1) | (0.0 × 100, 2.6 × 10−1) | |
| Meat-to-cutting board (low dose) |
5.70 × 10−3 | 1.00 × 10−3 | 1.90 × 10−4 | 2.80 × 10−4 | 4.10 × 10−5 | 7.30 × 10−6 | 1.40 × 10−6 | 2.00 × 10−6 | 1.00 × 10−2 | 1.80 × 10−3 | 3.40 × 10−4 | 5.00 × 10−4 |
| (5.1 × 10−4, 6.1 × 10−2) | (5.2 × 10−5, 1.5 × 10−2) | (3.1 × 10−6, 3.2 × 10−3) | (0.0 × 100, 4.8 × 10−3) | (3.6 × 10−6, 5.5 × 10−4) | (3.7 × 10−7, 1.1 × 10−4) | (2.2 × 10−8, 2.3 × 10−5) | (0.0 × 100, 3.5 × 10−5) | (9.0 × 10−4, 1.1 × 10−1) | (9.3 × 10−5, 2.7 × 10−2) | (5.5 × 10−6, 5.7 × 10−3) | (0.0 × 100, 8.6 × 10−3) | |
| Meat-to-knife (high dose) |
2.80 × 10−1 | 1.00 × 10−1 | 1.20 × 10−2 | 7.90 × 10−3 | 7.80 × 10−3 | 1.10 × 10−3 | 9.00 × 10−5 | 5.80 × 10−5 | 5.00 × 10−1 | 1.90 × 10−1 | 2.20 × 10−2 | 1.40 × 10−2 |
| (2.4 × 10−1, 3.2 × 10−1) | (7.5 × 10−2, 1.3 × 10−1) | (8.2 × 10−3, 1.7 × 10−2) | (5.3 × 10−3, 1.1 × 10−2) | (5.2 × 10−3, 1.1 × 10−2) | (7.1 × 10−4, 1.6 × 10−3) | (6.0 × 10−5, 1.3 × 10−4) | (3.8 × 10−5, 8.4 × 10−5) | (4.3 × 10−1, 5.6 × 10−1) | (1.4 × 10−1, 2.4 × 10−1) | (1.5 × 10−2, 3.1 × 10−2) | (9.4 × 10−3, 2.0 × 10−2) | |
| Meat-to-knife (low dose) |
6.30 × 10−3 | 8.70 × 10−4 | 7.30 × 10−5 | 4.70 × 10−5 | 4.60 × 10−5 | 6.20 × 10−6 | 5.20 × 10−7 | 3.30 × 10−7 | 1.10 × 10−2 | 1.60 × 10−3 | 1.30 × 10−4 | 3.80 × 10−5 |
| (4.2 × 10−3, 9.1 × 10−3) | (5.7 × 10−4, 1.3 × 10−3) | (4.7 × 10−5, 1.1 × 10−4) | (3.0 × 10−5, 6.8 × 10−5) | (3.0 × 10−5, 6.7 × 10−5) | (4.0 × 10−6, 9.0 × 10−6) | (3.4 × 10−7, 7.5 × 10−7) | (2.1 × 10−7, 4.8 × 10−7) | (7.4 × 10−3, 1.6 × 10−2) | (1.0 × 10−3, 2.2 × 10−3) | (8.4 × 10−5, 1.9 × 10−4) | (5.4 × 10−5, 1.2 × 10−4) | |
| Transfer from Typical Kitchen Surfaces | ||||||||||||
| Countertop | 6.30 × 10−6 | 1.20 × 10−6 | 2.10 × 10−7 | 3.10 × 10−7 | 4.50 × 10−8 | 2.80 × 10−9 | 1.50 × 10−9 | 2.20 × 10−9 | 1.10 × 10−5 | 2.10 × 10−6 | 3.70 × 10−7 | 5.50 × 10−7 |
| (5.1 × 10−7, 1.3 × 10−4) | (6.2 × 10−8, 2.7 × 10−5) | (5.0 × 10−9, 5.0 × 10−6) | (1.0 × 10−10, 7.8 × 10−6) | (3.6 × 10−9, 9.0 × 10−7) | (4.4 × 10−10, 1.9 × 10−7) | (3.5 × 10−11, 3.6 × 10−8) | (7.1 × 10−13, 5.6 × 10−8) | (9.0 × 10−7, 2.3 × 10−4) | (1.1 × 10−7, 4.8 × 10−5) | (8.8 × 10−9, 8.9 × 10−6) | (1.8 × 10−10, 1.4 × 10−5) | |
| Hand towel | 1.60 × 10−6 | 2.90 × 10−7 | 2.00 × 10−9 | 0.00 × 100 | 1.10 × 10−8 | 2.10 × 10−9 | 1.40 × 10−11 | 0.00 × 100 | 2.80 × 10−6 | 5.20 × 10−7 | 3.60 × 10−9 | 0.00 × 100 |
| (2.2 × 10−7, 1.5 × 10−5) | (2.6 × 10−8, 3.1 × 10−6) | (0.0 × 100, 5.4 × 10−7) | (0.0 × 100, 7.8 × 10−7) | (1.6 × 10−9, 1.1 × 10−7) | (1.9 × 10−10, 2.2 × 10−8) | (0.0 × 100, 3.8 × 10−9) | (0.0 × 100, 5.5 × 10−9) | (3.9 × 10−7, 2.6 × 10−5) | (4.7 × 10−8, 5.4 × 10−6) | (0.0 × 100, 9.5 × 10−7) | (0.0 × 100, 1.4 × 10−6) | |
| Dish cloth | 1.60 × 10−6 | 3.00 × 10−7 | 5.50 × 10−8 | 8.10 × 10−8 | 1.20 × 10−8 | 2.10 × 10−9 | 3.90 × 10−10 | 5.70 × 10−10 | 2.90 × 10−6 | 5.30 × 10−7 | 9.80 × 10−8 | 1.40 × 10−7 |
| (2.1 × 10−7, 1.6 × 10−5) | (2.6 × 10−8, 3.4 × 10−6) | (1.1 × 10−9, 6.9 × 10−7) | (0.0 × 100, 1.0 × 10−6) | (1.5 × 10−9, 1.1 × 10−7) | (1.8 × 10−10, 2.4 × 10−8) | (7.7 × 10−12, 4.9 × 10−9) | (0.0 × 100, 7.3 × 10−9) | (3.8 × 10−7, 2.9 × 10−5) | (4.6 × 10−8, 6.0 × 10−6) | (1.9 × 10−9, 1.2 × 10−6) | (0.0 × 100, 1.8 × 10−6) | |
| Kitchen sponge | 3.90 × 10−6 | 7.30 × 10−7 | 1.30 × 10−7 | 1.90 × 10−7 | 2.80 × 10−8 | 5.10 × 10−9 | 9.30 × 10−10 | 1.40 × 10−9 | 6.90 × 10−6 | 1.30 × 10−6 | 2.30 × 10−7 | 3.40 × 10−7 |
| (4.3 × 10−7, 4.4 × 10−5) | (5.3 × 10−8, 9.1 × 10−6) | (2.3 × 10−9, 1.9 × 10−6) | (1.3 × 10−9, 2.8 × 10−6) | (3.1 × 10−9, 3.1 × 10−7) | (3.7 × 10−10, 6.5 × 10−8) | (1.6 × 10−11, 1.3 × 10−8) | (9.1 × 10−12, 2.0 × 10−8) | (7.7 × 10−7, 7.8 × 10−5) | (9.4 × 10−8, 1.6 × 10−5) | (4.1 × 10−9, 3.3 × 10−6) | (2.3 × 10−9, 4.9 × 10−6) | |
| b. Risk reduction factor a with different hand washing protocols compared to “no washing”. | ||||||||||||
| Control Bar | Antimicrobial #1 | Antimicrobial #2 | ||||||||||
| Transfer from Meat Preparation Surfaces | ||||||||||||
| Cutting board-to-meat (high dose) | 5.5 | 32 | 21 | |||||||||
| Cutting board-to-meat (low dose) | 5.9 | 33 | 22 | |||||||||
| Knife-to-meat (high dose) | 4.9 | 29 | 19 | |||||||||
| Knife-to-meat (low dose) | 5.6 | 31 | 21 | |||||||||
| Meat-to-cutting board (high dose) | 3.2 | 14 | 10 | |||||||||
| Meat-to-cutting board (low dose) | 5.7 | 30 | 20 | |||||||||
| Meat-to-knife (high dose) | 2.8 | 23 | 35 | |||||||||
| Meat-to-knife (low dose) | 7.2 | 86 | 134 | |||||||||
| Transfer from Typical Kitchen Surfaces | ||||||||||||
| Kitchen surface | 5.3 | 30 | 20 | |||||||||
| Hand towel | 5.5 | 800 | >800 | |||||||||
| Dish cloth | 5.3 | 29 | 20 | |||||||||
| Kitchen sponge | 5.3 | 30 | 21 | |||||||||
a = Determined by comparing the median estimated risk from “no washing” to the median risk after washing with each of the three bar soaps. Calculations using the recommended best fit model are shown. b = Could not be calculated since the median estimated risk was 0.0 × 100.