Abstract: A transportable apparatus for microbiological investigations and examinations, particularly for determining numbers of microorganisms in surface samples taken from foodstuffs, walls, etc. using a sterile rinsing liquid atomized by a compressed gas. The apparatus, which may be shaped like a pistol is provided with a container for collecting the mixture of compressed gas, rinsing liquid and rinsed-off particles and a compressed gas supply connection is provided with a valve. The nozzle of the apparatus is placed on and pressed against the surface under investigation, after which the rinsing liquid is applied by the compressed gas to the surface under investigation and is subsequently collected in the container.