EVALUATE THE LIVING AND DEATH RATES OF PROBIOTIC IN YOGURT PRODUCTS BY UTILIZING FLOW CYTOMETRY TECHNIQUE

Abstract

The goal of this paper was developing a new method to determine the amount of beneficial probiotic
microorganisms living in products instead of the traditional plate counting method. This method was
applied to assess live/dead baclight bacterial viability and counting kit, in combination with flow
cytometry method (FCM) for zoning, distinguish living probiotics bacteria, dead bacteria and
determining total number of bacteria in yogurt products in a short time. The results of the study showed
that the rate of living bacteria was from 98.2% to 99.9% when staining with SYTO9 and the rate of
dead bacteria was from 85.7% to 99.6% when staining with PI in some samples.