The Effect of pH and Temperature on Motility of Listeria Species

The effect of pH of the medium and temperature of incubation was studied on motility of four strains of 2 Listeria species. All the strains were found to be non-motile at pH 4. The motility was observed at a pH range of 5.5 to 9.0. However, the optimum pH and temperature for motility was 7.0 and 22°C respectively. The strains NCTC 7973 and C-274 were, however, motile at pH 5.0. At pH 10, NCTC 5214 m, C-274 and NCTC 7973 were motile at 22°C with the exception of C-274 which was motile also at 35°C. NCTC 5214 m was motile at pH 11 only at 22°C whereas C-274 was motile at both 22 and 35°C.