Comparison of Airborne Microflora Collected by the Andersen Sieve Sampler and RCS Sampler in a Dairy Processing Plant

The performance of a Reuter centrifugal air sampler (RCS sampler) was compared with that of an Andersen 6-stage sieve sampler (Andersen impactor) to determine the suitability of the RCS sampler for monitoring airborne microflora in dairy processing plant environments. The types of microorganisms recovered from non-mold colony forming particles using the Andersen impactor and the RCS sampler were different at each location and trial. When selected Gram positive cocci and Gram negative rods were classified using Staph track and API 20E System, respectively, results indicated that the type of bacteria collected using each sampler was similar, though the percentage distributions were different. In addition, bacterial types were not consistently associated with different size particles. The RCS sampler was able to recover most bacterial types since these types were distributed over various particle sizes. When airborne fungi were collected, the RCS sampler recovered significantly lower amounts than that of Andersen impactor. The RCS sampler is suitable for use when approximate concentration of non-mold airborne particles, or relative degree of air cleanliness information is needed.