A method for the detection of bacteria in aqueous fluids in the form of solutions, emulsions and or suspensions, such as drinking water, liquid food and drinks and biological fluids such as urine, spinal and or amniotic fluids and serums by measuring light scattering The fluid suspected of containing bacteria is filtered first to exclude particles of sizes larger than the size of the expected bacteria. Other filtration methods are used in addition to exclude different constituents of the examined fluid. Ion exchange chromatography is such a method. The verification of bacterial contamination and the derivation of its level is performed by matching measured scattering profiles with pre-stored calibrated scattering profiles. A system for carrying out the measurements including cuvette units suited for light scattering measurements is provided Reference.