Tests described in this paper show that gelatine membrane filters used
in the MD8 microbiological air sampling system collected monodisperse
d aerosols between 0.7 and 1.0 mu m containing viable Bacillus subtili
s var. niger spores, with an efficiency of 99.9995%. Gelatine membrane
filters linked to the MD8 control pump system were as effective as th
e well established Casella slit-to-agar device for collecting some via
ble bacteria, nebulized under controlled experimental conditions and n
aturally occurring airborne micro-organisms in a pharmaceutical plant.
By using a long flexible hose connection to the control pump, the hea
d could be positioned where sampling was required in locations remote
from the pump exhaust, making it suitable for microbiological monitori
ng in critical locations such as laminar flow stations and isolators.