TABLE 2.
MICs of licochalcone A, protamine, and ɛ-poly-l-lysine against food contaminant bacteria in the presence of either NaCl or protease
| Compound | Incubation time (days)a | MIC (μg/ml) against the following organism under the indicated conditions:
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
B. subtilis IFO 3007
|
S. aureus IFO 12732
|
||||||||||
| % NaCl (wt/vol)
|
Protease at 20 μg/ml | % NaCl (wt/vol)
|
Protease at 20 μg/ml | ||||||||
| 0 | 1 | 2 | 3 | 0 | 1 | 2 | 3 | ||||
| Licochalcone A | 2 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| 7 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | |
| Protamine | 2 | 6.0 | 15.0 | 100 | 300 | 25.0 | 3.0 | 6.0 | 6.0 | 600 | 6.0 |
| 7 | 6.0 | 25.0 | 300 | 300 | 25.0 | 3.0 | 15.0 | 300 | >600 | 25.0 | |
| ɛ-Poly-l-lysine | 2 | 3.0 | 3.0 | 6.0 | 15.0 | 6.0 | 2.0 | 2.0 | 15.0 | 300 | 2.0 |
| 7 | 3.0 | 3.0 | 6.0 | 100 | 6.0 | 3.0 | 6.0 | 600 | >600 | 2.0 | |
a
MICs were determined by measuring the turbidity at 610 nm after 2 or 7 days of incubation at 30°C.