Tuesday, 22 May 2012

ATP Meters

Over the past ten years or so, a great deal of emphasis has been placed on the use of bioluminescence technology in the detection of micro-organisms.

The mechanism by which fireflies produce a flash of light was first analyzed and identified by William McElroy in 1947 . McElroy found that central to the light emission process was a specific enzyme reaction catalyzing the consumption of adenosine triphosphate (ATP).  In microbes, ATP can only be detected when living cells are present.

It has since been established that the amount of light emitted from this reaction is directly proportional to the amount of ATP present. A high reading of relative light units (RLUs) indicates that the sample contains a high number of micro-organisms, provided that the background ATP level is low. Unlike traditional testing methods, results from a bioluminescent reaction can be obtained quickly. Light is produced within seconds and can be measured with a luminometer (ATP Meter).

I have reviewed several ATP Meters on the market, for example, those from Celsis International and Biotrace.  However, for application in the bottled water industry I would recommend SystemSURE II from Hygiena.  This palm-sized instrument brings together state-of-the-art photodiode technology with simple user-friendly design to produce an affordable hygiene-monitoring system. Used with Ultrasnap ATP swabs, levels of contamination can be determined in just 15 seconds.

 Because bacterial counts in water are very low, a sample enrichment process is necessary. The process will be described in a later Blog. Key features of the luminometer include, low cost, high sensitivity, compactness, simple to use,self-calibrating with background check. Readings may be down-loaded onto a PC or, as an optional extra, analysis software will provide spreadsheet-compatible data.

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