biologic or non biologic the system also may produce an alarm signal or other response if biological particles are detected and or if the number of particles exceeds a predetermined threshold value for example the number of detected particles is above a normal background level fig2 6 are illustrations of a preferred embodiment for a fluid particle detector system according to the present invention as shown in fig5 and 6 the system includes an excitation source 112 such as a laser providing a beam of electromagnetic radiation 114 having a source wavelength the excitation source is selected to have a wavelength capable of exciting intrinsic fluorescence from metabolites inside microbes and biological particles the excitation source is also chosen to have a wavelength suitable for detecting mie scattering from particles for the determination of particle size examples of suitable excitation sources include uv light and visible light radiation sources such as uv light and visible e light lasers leds and the like by way of example the excitation source 112 preferably operates in a wavelength of about 270 nm to about 410 nm preferably about 350 nm to about 410 nm a wavelength of about 270 nm to about 410 nm is chosen based on the premise that microbes and biological particles comprise three primary metabolites tryptophan which normally fluoresces at excitation wavelengths of about 270 nm with a range of about 220 nm about 300 nm nicotinamide adenine dinucleotide nadh which normally fluoresces at excitation wavelengths of about 340 nm range about 320 nm about 420 nm and riboflavin which normally fluoresces at excitation wavelengths of about 400 nm range about 320 nm about.