Surface sampling is an essential part of environmental monitoring. But how reliable are the methods and what are they actually informing about the number of organisms attached to different Surfaces that can be consistently recovered? Tim Sandle has constructed a study with the aim of assessing how efficient the contact plate is for recovering microorganisms from cleanroom surfaces. The focus was to provide information of use to microbiologists in terms of developing a robust approach, as well as for understanding method limitations.

The outcome has been published in Chemistry Today. Here is the abstract:

This study was undertaken to determine whether TSA contact plates, formulated with a disinfectant neutralizer, were suitable for use in the detection and enumeration of microorganisms from surfaces for environmental monitoring sampling as relating to a pharmaceutical facility. Contact plates are the primary method of choice for quantitatively sampling flat surfaces and floors for the presence of microorganisms.

For the study a range of representative microorganisms were selected, and two surface material types were used: stainless steel and vinyl. The results showed a variable recovery across the two different surfaces and between the different types of microorganisms, with a mean of 55% for a 10 second contact time. This information demonstrates the relative efficiency of the contact plate for cleanroom environmental monitoring.

The study can be accessed here: Chemistry Today

The reference is:

Sandle, T. (2019) Assessment of the recovery of different bacteria from two Cleanroom Surface Materials, Chimica Oggi-Chemistry Today, 37 (5):  31-33 

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology