Minimum growth temperatures ofListeria monocytogenesand non‐haemolytic listeria

摘要

Minimum growth temperatures and those of decreased growth were determined for 100 strains of listerias. The ability of 78 strains ofListeria monocytogenesisolated from animals and 22 non‐haemolytic strains to grow at low temperatures was studied, using a flooding technique, in a plate‐type continuous temperature gradient incubator at temperatures between –1.6 and 14.5.C. The mean minimum temperature forL. monocytogeneswas +1.1 0.3.C. The growth of non‐haemolytic listerias was unobservable at +1.7 0.5.C. TheL. monocytogenesstrains grew at about 0.6°C lower than the non‐pathogenic strains. No differences in growth temperatures were observed amongL. monocytogenesstrains isolated from different sources. The serovars with the OI antigen grew at lower temperatures (+1.0.3°C) than the other common serovar 4b (+1.3 0.4°C).The results indicate thatL. monocytogenesgrows better than non‐haemolytic strains under cold conditions. The possible role of haemolysins as growth factors is