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Equipment Use

Culture Media

Published: June 4th, 2009

Revised: September 24th, 2009

A number of environmental sampling methods exist that allow samples to be taken directly on culture media. The most common methods are viable air samplers such as RCS and Andersen samples as well as contact surface slides. If proprietary sampling media are used, ensure that the expiry date is current. In accordance with our internal quality assurance protocols, stale-dated sampling media cannot be processed. RCS stripOn RCS sample strips, the expiry date is usually hot-stamped on the tongue of the strip on the end where the strip is opened. Petri plates prepared by media supply houses normally stamp expiry dates on the plate bottom. If you are uncertain, please do not hesitate to contact us for assistance.

Once samples are taken, ensure that the medium container or transport sleeve is re-sealed with tape to protect the agar from drying during incubation. Samples where the growth medium shows signs of drying may produce inaccurate results, and will be noted on the laboratory report. Agar strips or plates should be clearly labeled using an indelible marker (e.g. “Sharpie” permanent markers) and packaged in a clean sample pouch (e.g. a Ziploc freezer bag) along with a completed laboratory submission form, and packed in a padded envelope or small box for shipping. Insulating materials may be of value in maintaining a constant temperature for your samples during shipping. Ice packs should not be used as cooling may damage the sampling media. Strips or plates must be received at the laboratory no later than 24 hr after the samples were taken. We regret that samples received beyond this time-frame or those lacking a submission form cannot be processed.