Abstract: A system and method for testing for microbial contamination using a digital flow cytometer comprising an illumination source, a fluorescence detector, a digitizing device, and a digitized signal transferring device.

Abstract: Apparatus for rapid, ultra sensitive and automatic counting of flourescent biological cells such as microorganisms, carried by a solid support such as a filter.

Abstract: Process for rapid, ultrasensitive and automatic counting of fluorescent biological cells such as microorganims, carried by a solid support such as a filter.The process includes: scanning a solid support on which a specimen potentially containing microorganisms has been deposited, with an incident beam from a laser, forming a laser spot on the solid support, the laser spot being substantially greater than the microorganisms to be detected, the laser spot size being between 4 and 14 .mu.m and simultaneously: detecting the resultant fluorescent light at least at one wavelength; establishing a set of correlated-features by a line-to-line correlation of individual features; comparing said correlated-features on each pair of adjacent lines in time synchrony, at least at two different wavelengths .lambda..sub.1 and .lambda..sub.