The ImpactAir-140 uses the larger 14 cm Petri dishes allowing the system to sample for longer periods onto a single dish. The sampling time is programmable from minutes to many hours. With a deep fill agar plate it is possible to sample for several hours onto a single agar plate. Sampling 1m³ of air is achieved in 35 minutes and 20 seconds with the flow rate of 1 cubic foot per minute.
With any impaction sampler, the distance between the inlet and the surface of the agar is critical and has a major effect on the sampling efficiency. The agar in Petri dishes is often not a constant depth so ImpactAir is the first sampler of its kind to employ precision sensing and control to automatically adjust the distance throughout an entire run to ensure a consistent d50 value is maintained. This is supported by results obtained from independent physical and biological validation carried out by Public Health England (PHE).
Unlike some other air samplers, due to its unique design, ImpactAir® does not shed particles. Therefore, it is able to operate in environments alongside particle counting devices without causing increased readings. ImpactAir® exhibits very low vibration and can therefore be operated near balances.
Exceptional biological efficiency
ImpactAir air monitors are based on the slit-to-agar method, which has very low d50 values of around 0.5µ with exceptional biological efficient and the ability to easily count real viable microbial events in CFU while being able to identify to species level.
Twin impingement probability reduced
Air is drawn at high speed through a narrow inlet. Particles and microbes are impacted on to agar in a rotating Petri dish. Fresh agar is presented constantly, significantly reducing the chance of multiple microbes appearing as a single colony after incubation.
Continuous monitoring using a 9cm agar plate
The rotating agar plate means results are time correlated. Whilst not timed to the second, localised growth on the plate can be time estimate based on its position on the plate.
Typical requirements suggest 1,000 litres per air sample in high risk areas, such as: grade A filling lines, grade B clean rooms, operating theatres etc. As the criticality of the area reduces, the sample size can be reduced. The aim is to achieve a representative sample; so where higher counts would be expected, a smaller sample produces a more realistic number of cfu to count.
SAS samplers were originally designed for Contact plates, however, a Petri dish option has been available for a number of years. It is really a personal choice, although this should be decided at time of purchase, as the sampler will be specifically configured for the plate type chosen. There are advantages for each version and we would be happy to discuss your specific needs.
No, do not put your SAS sampler in a steam autoclave. The only part that can be autoclaved is the drilled head. The unit can be wiped with alcohol wipes to decontaminate it. The only other exception is the SAS Pinocchio, parts of which can be autoclaved.
Cherwell Laboratories recommends every 12 months and we will send a reminder for the month it is due. For some situations local procedures demand more frequent recalibrations so Cherwell is happy to offer tailored recalibration date labelling and reminders on request.
The sterility of the packaged medium is assured and all but the outer layer of packaging is also sterile. Thus the risk to the environment to be sampled is greatly reduced. There is an additional benefit that the additional packaging and process extends the room temperature shelf life. This can be sufficient reason for small or irregular users to prefer irradiated.
Settle plates are used to monitor the level of viable particles in the environment through a process of passive air sampling. A viable particle settles on agar plates at a rate dependent on its characteristics and the airflow in the environment.
EU GMP Guide Annex 1 has recommended that 90mm settle plates can be exposed in cleanroom environments for up to 4 hours. However, agar plates may dry out during long exposures where the rate of air exchange is high. So, it might be necessary to use deep filled settle plates, or replace the settle plate after a shorter time to ensure satisfactory growth promotion after exposure.
The storage condition for the majority of our prepared media is Ambient not exceeding 25ºC, the exception being a couple of very specialist products.
We have never specified storage in a fridge for our general media as this causes excessive condensation and can result in a very wet agar surface. This makes the product impossible to use.
General purpose media have nutrients that support the growth of most non fastidious culturable microorganisms. Selective growth media contain components that will inhibit the growth of some types of microorganisms, while supporting the growth of others.
General purpose media, such as Tryptone Soya Agar, are used to produce total counts. While selective media, such as XLD for Salmonella species, are used to test presence/absence of specific types of microorganism.