Microviable particle counting system and microviable particle counting method

A microviable particle counting method comprising:

• irradiating a sample as fluid with ultraviolet light;
• and
• detecting autofluorescence of a microviable particle in the sample irradiated with the ultraviolet light, thereby counting the microviable particle in the sample,
• wherein the sample includes a humic substance emitting fluorescence leading to background noise on the autofluorescence of the microviable particle,
• the ultraviolet light contains first ultraviolet light and second ultraviolet light, the first ultraviolet light having a wavelength shorter than 200 nm so that a carbon-carbon covalent bond is disconnected, the second ultraviolet light having a wavelength longer than that of the first ultraviolet light within a UV-C wavelength range,
• no aeration for the sample is performed during the irradiating the sample, and
• the intensity of the fluorescence leading to the background noise is lower than the intensity of the autofluorescence of the microviable particle.

A microviable particle counting system comprising:

• 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, wherein
• the ultraviolet light contains first ultraviolet light having such a wavelength that a carbon-carbon covalent bond is disconnected,
• the first ultraviolet light has a wavelength shorter than 200 nm,
• the former-stage irradiator includes a light source configured to emit the ultraviolet light, a flow passage portion disposed at a periphery of the light source such that the sample circulates in the flow passage portion, and a shield configured to cover the light source and the flow passage portion to reflect or absorb the ultraviolet light,
• the light source includes a light emitter configured to emit the ultraviolet light,
• the flow passage portion is a cylindrical case, and is configured to house the light source along a center axis inside the flow passage portion, and
• a sample outlet port is, at the flow passage portion, provided at a position identical to or higher than an upper end of the light emitter above a sample inlet port of the flow passage portion.