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Rapid counting of liquid-borne microorganisms by light scattering spectrometry.

Authors
Mainelis-G; Gorny-R; Willeke-K; Reponen-T
Source
Ann Agric Environ Med 2005 Jan; 12(1):141-148
NIOSHTIC No.
20028866
Abstract
Fast and sensitive techniques are needed to determine microorganism presence in liquid samples. In this research, the feasibility of using light scattering spectrometry for enumerating the biological particles in liquid samples was investigated. A particle size spectrometer was used to count six commonly found microbial species suspended in liquid with and without microbiological stains applied: Pseudomonas fluorescens, Micrococcus spp. vegetative cells and Bacillus subtilis var. niger endospores were stained with Acridine Orange and Crystal Violet, while Cladosporium cladosporioides, Penicillium melinii and Aspergillus versicolor fungi were stained with Acridine Orange and Lactophenol Cotton Blue. The counts obtained with the spectrometer were compared with those obtained with a phase-contrast microscope. It was found that the spectrometer counted about 32 % of non-stained B. subtilis endospores and this percentage increased to almost 90 % for stained endospores. Among the investigated species of fungi, the counting efficiency of P. melinii was the only one significantly affected by the application of the stain Lactophenol Cotton Blue: the fraction of counted fungal spores increased from 64 % (non-stained spores) to about 100 % (stained spores). The observed difference in counting efficiency may serve as a basis for differentiating biological from non-biological particles in liquid samples.
Keywords
Microorganisms; Sampling; Fungi; Fungicides; Biological-agents; Bacteria
CODEN
AAAEFJ
Publication Date
20050101
Document Type
Journal Article
Email Address
mainelis@envsci.rutgers.edu
Funding Amount
933298
Funding Type
Grant
Fiscal Year
2005
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003463
Issue of Publication
1
ISSN
1232-1966
Priority Area
Research Tools and Approaches: Exposure Assessment Methods
Source Name
Annals of Agricultural and Environmental Medicine
State
NJ; OH
Performing Organization
University of Cincinnati
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