Table 6.
Effects of temperature and pH on the antimicrobial activity of ZZU 203 and 204
| Treatment | Antimicrobial activity | ||||||
|---|---|---|---|---|---|---|---|
|
| |||||||
| Salmonella enterica ATCC 43971T | Escherichia coli ATCC 11775T | Micrococcus luteus ATCC 4698T | |||||
|
|
|
|
|||||
| ZZU 203 | ZZU 204 | ZZU 203 | ZZU 204 | ZZU 203 | ZZU 204 | ||
| Heat (°C) | 60, 30 min | +++ | ++ | ++ | ++ | ++++ | ++++ |
| 60, 60 min | +++ | ++ | ++ | ++ | +++ | ++++ | |
| 80, 30 min | +++ | ++ | + | ++ | +++ | +++ | |
| 80, 60 min | +++ | ++ | + | ++ | +++ | +++ | |
| 100, 30 min | ++ | ++ | + | ++ | +++ | +++ | |
| 100, 60 min | ++ | ++ | + | ++ | +++ | +++ | |
| 121, 15 min | − | − | − | − | − | − | |
| pH | 2.0 | +++ | +++ | +++ | +++ | +++ | +++ |
| 3.0 | ++ | +++ | ++ | ++ | +++ | +++ | |
| 4.0 | ++ | ++ | ++ | ++ | +++ | +++ | |
| 5.0 | ++ | ++ | + | + | +++ | ++ | |
| 6.0 | + | ++ | + | + | ++ | ++ | |
| 7.0 | − | − | − | − | − | − | |
| 8.0 | − | − | − | − | − | − | |
| 9.0 | − | − | − | − | − | − | |
+, Diameter of inhibition zone: 8.00 to 12.00 mm; ++, 12.00 to 16.00 mm; +++, 16.00 to 20.00 mm; ++++, more than 20.00 mm; −, no inhibition zone; the diameter of inhibition zone including that of Oxford cup (7.80 mm).