| Abstract: | Listeria monocytogenes serotype 1 and Scott A strains were examined to determine the effect of culture conditions onproduction of listeriolysin O (LLO). The hemolytic activity was assayed by hemolysis of sheep red blood cells. The optimum pH range for LLO production in serotype 1 and Scott A were pH 6.2–6.0 and pH 5.8–6.0, respectively. Production of LLO by serotype 1 was 20–fold higher than by Scott A. Addition of more than 1.0% glucose significantly reduced production of LLO by the cells, while favoring growth. By adding 0.5% glucose after stationary phase and adjusting pH to 5.5–7.0, maximum LLO was produced after 2 h incubation at 37C by both strains. |
