抄録
Growth inhibition of bacteria in chicken bone soup by four ground spices used commonly for the soup, namely clove, thyme, laurel and black pepper, was investigated. Bacterial growth was measured by the plate colony count method.
1. Commercially available ground spices especially black pepper were contaminated with spore forming bacteria. Therefore black pepper and thyme suspended in the soup were autoclaved at 121°C for 20 min. and 10 min., respectively and the soup suspended clove and laurel was gently boiled for 5 min.
2. Each spice was added into the soup at the same concentration. The soup with spices was distributed into sterile open bottles. These bottles were kept in the laboratory for 30 min., then capped and stored in a room at 23°C. Growth inhibition of bacteria in the soup was observed in the presence of 0.05% each of four spices, and complete prevention of the growth for 9 days was achieved by adding 0.125%, each.
3. Escherichia coli IFO 3301 inoculated into the sterilized soup was little sensitive against 0.125% each spice. But the growth of Staphylococcus aureus IFO 3761 was inhibited by 0.05%each, and in the presence of 0.125% each, these spices exhibited bactericidal activity. In the soup adjusted to pH 5.0 with acetic acid, E. coli did not grow regardless of spices, however the growth of S. aureus was inhibited in proportion to the concentration of spices, yet the bacteria could grow a little up to 0.125% each.
4. Comparisons of growth inhibition of S. aureus by some assortments of these spices indicated that any of these four spices contributed to the inhibition, but clove was most effective.
5. The soup supplemented into bouillon medium suppressed the antibacterial activity of clove extract against S. aureus.
