COMPARISON OF ENZYMATIC CHEMILUMINESCENT ASSAY AND STANDARD AGAR PLATE METHOD IN THE DETERMINATION OF BACTERIAL VIABILITY

Abstract

ABSTRACT Menadione‐catalyzed luminol chemiluminescence (LC) assay has been proposed for the rapid determination of bacterial viability. This study demonstrated desirable conditions for rapid detection of viable bacteria in a liquid medium using LC assay. The possibility of using this assay for the assessment of the activity of an antimicrobial agent such as bovine lactoferrin against Pseudomonas fluorescens 33 and Escherichia coli 1649™, which are present in milk, was also investigated. Good correlation was observed between LC assay and standard agar plate technique. The antibacterial effect of lactoferrin was similar whether estimated using LC assay or standard agar plate technique. These results suggest that LC assay can be a rapid and useful method to replace the standard plate technique.PRACTICAL APPLICATIONSMenadion‐catalyzed luminol chemiluminescence (LC) assay, which detects photon emissions of living organisms, is a sensitive method for monitoring viability. The most commonly used standard agar plate technique requires a long time to enumerate cell growth in a medium. Moreover, the optical density method has defects in differentiation of living and dead cells. In contrast, LC assay is simple, rapid and sensitive for the enumeration of viable cells in a medium.