A modification of the resazurin cell viability assay, suitable for the quantification of lactic acid producing bacteria

Abstract

The conventional resazurin cell viability assay is based on the conversion of resazurin into the fluorescent molecule resorufin in the presence of metabolically active cells. Nevertheless, this method encounters limitations derived from medium acidification by lactic acid bacteria. Here we propose a two-step modification of the resazurin method for accurate lactic acid bacteria growth and prebiotic assessment without pH interference. Using a polyphenolic extract from Cytisus scoparius as a test prebiotic, this study demonstrates the efficacy of a two-step resazurin assay in quantifying lactic acid bacteria growth underscoring the importance of innovative methodologies for prebiotics screening.