| The microbiological control of clean rooms and controlled environments has become a key element of the quality assurance program of pharmaceutical production sites. Traditionally, these controls are based on the collection of micro-organisms on to a media plate followed by incubation over several days. After the growth period, the contamination level is determined by enumeration of the visible colonies on the plate.
This method is simple but has the disadvantage of providing results 3 to 5 days after the sample collection. This means real time corrective action is not possible.
Moreover, the traditional method does not enumerate all micro-organisms present in the air, because "stressed" or slow growing micro-organisms require longer recovery times.
New ultra-rapid method: Polym'Air + Solid-Phase Cytometry
The fluorescent labelling of viable micro-organisms coupled with membrane solid-phase cytometry has been developed to meet the need for speed and sensitivity in the pharmaceutical industry. Solid-phase scanning cytometry is widely used for the real time enumeration of micro-organisms in process water or for the bio burden of filterable products.
Sampling of airborne micro-organisms
The method uses a sterile water-soluble gel called Polym'Air . This synthetic compound, composed of long molecular chains, doesn't contain any nutrients (ready-to-use in a standard 90 mm Petri dish).This inert and non selective polymer allows the collection of all micro-organisms including stressed or slow-growth micro-organisms.
An air sample is collected using an air sampler. (The new Sampl'Air from AES Laboratoire allows the automatic traceability of operator, Polym'Air plate and sampling location through bar code identification and 21CFRpart11 compliant software). After sampling, 40 ml of sterile Fluid A is added to dissolve the polymer. The solution is then filtered on a 0.4µm membrane in order to concentrate the micro-organisms.
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Polym'Air plate | 
Laser scanning using ChemScan® RDI | Labelling and counting within 3 hours
The fluorescent labelling of the viable micro-organisms present at the surface of the filter is carried out according to the standard protocol developed and validated for the analysis of process water. A unique protocol allows the simultaneous enumeration of mesophilic bacteria, (sporulated or not), yeasts, mycelium, and mould spores within 3 hours Up to 4 series of 6 membranes can be labelled simultaneously. The scanning using the ChemScan® RDI cytometer (Chemunex) takes 3 minutes per membrane.
| * The laser scanning cytometer, the polymer and the air sampler are marketed by AES Chemunex under the names ChemScan®RDI, Polym' Air® and Sampl'Air®.
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