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Fluorescence microscopy procedure for quantitation of yeasts in beverages
Applied and Environmental Microbiology
|September 1, 1986
Summary
A new fluorescence microscopy method using aniline blue accurately quantifies yeasts in beverages. This technique offers a faster and more reliable alternative to traditional plate and hemacytometer counts for yeast enumeration.
Area of Science:
- Microbiology
- Analytical Chemistry
- Food Science
Background:
- Traditional yeast quantitation methods like plate counts and hemacytometer counts are time-consuming and have limitations in accuracy and sensitivity.
- Plate counts only detect viable yeast cells, while hemacytometer counts are only reliable at very high cell concentrations.
Purpose of the Study:
- To develop and validate a novel, efficient, and accurate method for quantifying yeast populations in beverage samples.
- To improve upon existing methods for yeast enumeration in the food and beverage industry.
Main Methods:
- Utilized fluorescence microscopy in conjunction with the fluorescent stain aniline blue for yeast differentiation and counting.
- Incorporated membrane filtration to concentrate yeast cells from liquid samples prior to enumeration.
Main Results:
- The new method demonstrated high recovery rates, averaging 91.5% for beverages spiked with yeast levels ranging from 500 to 600,000 cells/ml.
- Achieved a high correlation coefficient (0.996) between cell counts and spiked levels, indicating excellent accuracy.
Conclusions:
- Fluorescence microscopy with aniline blue provides a rapid and reliable method for yeast quantitation in beverages.
- This technique, especially when combined with membrane filtration, offers a significant improvement over conventional methods for yeast enumeration.