Monday, 5 November 2018

Avoiding environmental monitoring ‘false negatives’

In addition to selecting the right culture media, the use of an appropriate neutraliser is important in relation to surface, and some personnel, monitoring. Neutralisers are required to overcome any residues left by disinfectants, as can be found on cleanroom surfaces or on the gloved hands of personnel. The use of a neutraliser within the culture media formulation is also necessary to overcome residues from antimicrobial compounds so that a false negative is avoided.

The use of a neutraliser is recommended in the biocontamination control standard ISO 14698;3 and, outside of pharmaceuticals, the cosmetics microbiological test standard ISO 21149 contains some useful advice on neutraliser selection.

Tim Sandle has written a new paper on the topic of neutralisers for culture media. The introduction reads:

“The selection of an appropriate neutraliser is not straightforward. The neutraliser must be non-toxic to the microorganisms expected to be recovered; be able to stop residual disinfectant activity; and, in use. This latter requirement often proves the most challenging. This article examines the most common neutralisers used; some of the problems associated with their selection; and the complexities around using the most appropriate neutralisers in the culture media most commonly used in the environmental monitoring programme.”

The reference is:

Sandle, T. (2018) Avoiding environmental monitoring ‘false negatives’: overcoming disinfectant residues with culture media neutralisers, European Pharmaceutical Review, 23 (4): 18-21

The article can be accessed here:

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

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