Comparing the efficiency of Epi-Fleuorocence Light Microscopy in investigating activity of bakey yeat (Saccharomyces cerevisiae) with conventional methods

Document Type : Research Paper


1 Professor of Food Technology, Department of Food Science, College of Agriculture, University of Tabriz

2 MSc graduated, Department of Food Science, College of Agriculture, University of Tabriz, Tabriz

3 Associate Prof. of Plant Organogenesis and Morphogenesis, Department of Horticultural Sciences, University of Tabriz, Tabriz

4 Associate Prof. of Food Hygiene, Faculty of Veterinary Medicine, University of Tabriz, Tabriz

5 Academic staff member, Iran National Standard Research Institute, Karaj, Iran.


Activity of three types of commercial bakery yeasts encoded as A-C was investigated by EFLM technique and compared to those of conventional methods such as Gasograph, microbial incubation and breadmaking. Double staining of yeast suspensions with FDA and Evance Blue in EFLM revealed green and red colors for live and dead yeast cells, respectively. Yeast A with the highest number of green (alive) cells (178 counted cells per microscopic image) and yeast B with the lowest number of surviving cells (102 counted cells) achieved the most and the least survival ranks, respectively. The most and least colony forming units (CFU) was obtained for yeast A (15×1010 cfu/mg) and C (12×1010 cfu/mg), respectively in microbial tests. In Gasography method, yeasts A and C produced the highest (163 mL CO2/3h) and lowest (140 mL CO2/3h) gas volumes, respectively. Similarly, in breadmaking tests the highest (132 cm3) and lowest (108 cm3) loaf volumes corresponded to yeasts A and C, respectively. Results indicated that there is a positive correlation between green yeast cells in EFLM, live yeasts in microbial test and the amount of gas produced in gasography analysis, and finally the loaf volume.


Main Subjects

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