Microviable particle counting system and microviable particle counting method
Inventors
Assignees
Publication Number
US-10094763-B2
Publication Date
2018-10-09
Expiration Date
2037-08-18
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Abstract
A microviable particle counting system includes: a microviable particle counting instrument configured to detect autofluorescence of a microviable particle in a sample as fluid, thereby counting the microviable particle in the sample; and a former-stage irradiator provided at a former stage of the microviable particle counting instrument to irradiate the sample with ultraviolet light. The ultraviolet light contains first ultraviolet light having such a wavelength that a carbon-carbon covalent bond is disconnected, and the first ultraviolet light has a wavelength shorter than 200 nm.
Core Innovation
The invention relates to a microviable particle counting system and method designed to accurately count microviable particles such as bacteria, yeast, or fungus in a sample fluid, even when the sample contains mixed organic substances emitting fluorescence that causes background noise on the autofluorescence of the microviable particles. The core innovation includes a microviable particle counting instrument configured to detect autofluorescence from microviable particles and a former-stage irradiator that irradiates the sample with ultraviolet light containing an ozone generation beam before counting.
The problem addressed is that conventional methods require long cultivation periods to measure bacteria levels in samples like mineral water, and autofluorescence-based real-time counting instruments face interference from organic substances such as humic acid or fulvic acid. These mixed organic substances emit fluorescence that overlaps the autofluorescence spectrum of the microviable particles, making accurate detection difficult and causing counting errors.
To solve this, the system irradiates the sample with ultraviolet light having a wavelength shorter than 200 nm that disconnects carbon-carbon covalent bonds, particularly an ozone generation beam, to decompose the mixed organic substances that cause background noise. This decomposes interfering fluorescence sources, enabling accurate microviable particle counting in real time or within a short time frame without cultivation. The ultraviolet irradiation is performed without aeration, preventing bubble formation and preserving counting accuracy.
Claims Coverage
The patent includes multiple independent claims focused on the structure and function of a microviable particle counting system and method featuring a former-stage irradiator with specific ultraviolet light characteristics.
Microviable particle counting system with a former-stage irradiator emitting ultraviolet light containing an ozone generation beam
A system comprising a microviable particle counting instrument detecting autofluorescence to count microviable particles, and a former-stage irradiator with a single light source that irradiates the sample with ultraviolet light containing first ultraviolet light shorter than 200 nm (disconnecting carbon-carbon bonds) and second ultraviolet light longer than the first within the UV-C range, without performing aeration, to reduce fluorescence background noise.
Former-stage irradiator including storage and submerged ultraviolet light emitter
The irradiator includes a storage to hold the sample and a flow passage to supply the sample to the counting instrument, where the light emitter is submerged entirely in the sample during irradiation.
Former-stage irradiator configured with a flow passage around the light source and ultraviolet light-reflecting shield
An irradiator design where the sample circulates in a flow passage arranged around the ultraviolet light source, which is covered by a shield that reflects or absorbs ultraviolet light to enhance irradiation efficiency and reduce leakage.
Flow passage portion as U-shaped tube or cylindrical case housing the light emitter
The flow passage can be a U-shaped tube extending around the light emitter or a cylindrical case housing the light source along the center axis, with inlet and outlet ports provided tangentially to induce circulation and ensure effective irradiation.
System where the sample is water and microviable particles contain riboflavin or NAD(P)H
The system targets microviable particles containing riboflavin or NAD(P)H in water samples, addressing fluorescence interference from humic substances via ultraviolet irradiation.
The claims collectively cover a microviable particle counting system and method that use specific ultraviolet irradiation in a former-stage irradiator to decompose fluorescence-causing organic substances in samples, enabling accurate autofluorescence-based counting without aeration, with various configurations of the irradiator and flow passages to optimize irradiation and counting performance.
Stated Advantages
The system enables accurate counting of microviable particles in real time or within a short period, even when mixed organic substances emitting fluorescence interference are present in the sample.
Decomposition of fluorescence-emitting organic substances by ultraviolet irradiation reduces background noise, improving detection sensitivity and counting accuracy.
Irradiation without aeration prevents interference from air bubbles, thereby enhancing reliability of measurement.
The system can count microviable particles without requiring lengthy cultivation, increasing efficiency in monitoring samples such as mineral water.
Documented Applications
Counting of microviable particles such as bacteria, yeast, and fungus in water samples including mineral water and tap water.
Measurement of microviable particle contamination levels in manufacturing lines in real time.
Monitoring of microviable particles in natural water sources and other samples containing organic substances that cause fluorescence background noise.
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