Total viable bacterial count using a real time all-fibre spectroscopic system.

Area of Science:

• Environmental microbiology
• Optical sensing technologies
• Water quality monitoring

Background:

• Accurate bacterial enumeration is crucial for environmental research.
• Standard methods like heterotrophic plate count are time-consuming (1-8 days) and less accurate.
• Existing rapid techniques are often costly and require specialized equipment.

Purpose of the Study:

• To develop and evaluate a computerized optical prototype for bacterial detection.
• To assess the system's potential for Total Viable Bacterial Count (TVBC) in water samples.
• To compare the performance of the optical system against standard bacterial counting methods.

Main Methods:

• Development of an all-fibre optical system utilizing fluorescence enhanced by nucleic acid staining.
• Employment of a diode-pumped solid-state laser and a CCD spectrometer for high sensitivity detection.
• In situ excitation and signal collection for bacterial enumeration.
• Application of multivariate analysis for data interpretation.

Main Results:

• The optical system demonstrated higher accuracy and significantly shorter detection times compared to standard methods.
• Relative standard deviation for the optical system ranged from 21-36%, versus 41-59% for heterotrophic plate count.
• The system effectively detected bacterial concentrations from 10^2 to 10^8 CFU/ml.

Conclusions:

• The developed all-fibre optical system provides a sensitive, accurate, and rapid method for bacterial enumeration in water.
• Advantages include near real-time analysis, portability, and broad detection concentration range.
• This technology offers a promising alternative to conventional, slower microbiological analysis techniques.