Rapid evaluation of bacteriolysis of Listeria innocua and L. welshimeri strains isolated from foods

Abstract

This study was performed to determine the bacteriolytic extent of 10 strains of Listeria innocua and 9 strains of L. welshimeri isolated from foods. Bacteriolysis was measured at 650 nm by spectrophotometer. For this purpose, late exponential phase cells were transferred into potassium phosphate buffer (100 mM, pH 7.0) and incubated at 37 degrees C. While the bacteriolysis range of L. innocua strains was 48% to 76% after 48 h of incubation, L. welshimeri isolates exhibited broader bacteriolytic variabilities, from 10% to 67%. A preliminary analysis of the bacteriolysis of L. innocua and L. welshimeri may be useful in detailed evaluations of the bacteriolytic system within the genus Listeria.