Determination of Viable Count in Food Samples with Rapid Live Bacteria Counter Using Cassette-Type Flow Cytometry

Abstract

A rapid live bacteria counter (Cassette Lab.), with a disposable cassette in which the number of live bacteria is counted rapidly, simply, and accurately, for ensuring food safety, was developed. Cassette Lab. has the following features: (1) Cassette Lab. automatically performs the following processes in the cassette: removing food debris, staining live and dead bacteria, and counting live bacteria by flow cytometry. (2) It uses multistaining (fluorescent-dye combination) optimized to make it easy to distinguish the fluorescence of live bacteria from the different fluorescence of food debris and dye particles. (3) When counting the number of live bacteria in meat and fish, bleaching fluorescent-dye after staining bacteria reduces false positive rates. The live bacteria count in test samples, obtained with Cassette Lab. and that obtained by conventional plating methods, are highly correlated (R (bacteria & yeasts): 0.90; R (vegetables): 0.96; and R (chicken leg): 0.97).