One such instrument, the SystemSURE Plus from Hygiena International, has the following features:
- Low background that minimises signal to noise ratio which maximises sensitivity and enables reliable detections at low ATP levels therefore reducing false positives.
- The output scale (Relative Light Units, RLU) is quantitative and 1 RLU=1 fmol ATP (higher RLU numbers do not mean higher sensitivity).
- Self-calibration that significantly reduces service and maintenance costs, and the low voltage supply means that simple AA pen battery can be used compared to expensive dedicated mains/re-chargeable systems.
- Secure data download to PC by either of two software options including advanced, simplified trend analysis (Sure Trend) with pre-defined and customised report generation at the click of a button.
- Other features include sampling plans, Re-test tag and trace function, on-screen statistical review of results without the need to download to PC.
The sample collection and testing devices are integrated all-in-one and ready-to-use, and contain a novel liquid-stable reagent formulation. These sampling/testing devices are available for solid surfaces (Ultrasnap) and for liquid samples (Aquasnap) such as CIP rinses and other water samples.
All sampling devices have a simple snap and squeeze activation step with 12-months shelf life and tolerance to ambient temperature abuse.
These devices are slim and light weight thus combining ease-of-use with reduced environmental impact because they contain fewer parts and are 50-60 per cent lighter than comparable products.
Low background noise
One of the features of the systems is the very low background noise that means that the system can clearly differentiate between results at very low RLU values unlike other systems. This low background confers a high degree of precision and sensitivity to the system at low ATP levels.
Campden-BRI (the largest membership based food and drink research centre in the world) was commissioned to test the SystemSURE Plus Instrument. While Campden-BRI does not endorse specific products or services its conclusions were that SystemSURE Plus produces accurate and repeatable results.
The ATP and the food residue detection experiments demonstrated the sensitivity and repeatability of the SystemSURE Plus system to detect ATP over a range of concentrations and for a range of food groups with reproducible results.
Testing systems
Accuracy and precision are a consequence of the variation of a method (as shown in Fig.1). In an extensive study conducted by independent international laboratory, accuracy and precision of different ATP systems were studied.
Fig.2 shows the results from 30 replicate samples of ATP tested directly in five test systems by the same analyst. Hygiena SystemSURE Plus was shown to be the most accurate and precise ATP test system because results have an acceptable standard error limits of +/-10 per cent.
Other systems can vary up to 130 per cent, which is highly imprecise and very inaccurate.
In addition, the Hygiena SystemSURE recovered most ATP from the swab and with the least variation thus enabling reliable, precise and accurate sample collection (see Fig.3). Accordingly, SystemSURE Plus with its low background noise, consistent and reproducible reagent performance with excellent sample collection and recovery delivers the best performance of repeatable, accurate and precise results.
The SystemSURE Plus is suitbale for use by large and small food processors, hospitals, restaurants, supermarkets, and other industries where rapid detection of contamination is critical. It allows companies to quickly determine the cleaning efficiency and hygienic status of surfaces and water, ensure product quality, and reduce costs.
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- Martin Easter is with Hygiena International Ltd, Watford, Herts, UK. www.hygiena.net.
