Development of a rapid method for process control of surface disinfection based on enzymatic detection of apathogens
IGF 16490 N
In hygienically demanding areas (e.g. food industry, pharmaceutics, cosmetics and health sector) routine cleaning and surface disinfections have to be performed in order to meet the high hygiene standards. The performance and frequency of these procedures are defined in hygiene and disinfection plans which are integrated constituents of quality management (QM) and quality assurance systems (QA). The basis for these systems is a mandatory hygiene control, a suitable documentation and the use of validated disinfection procedures. Currently the only possibility to evaluate the hygiene of a surface after disinfection is a random end product control. These controls are generally performed via Replicate Organism Detection and Counting (RODAC)-plates. The results, however, are available after a minimum of two days. Because of this delay, an insufficient disinfection (caused e.g. by an inadequate dosage, protein- or soap-mistake) is recognized late.
The wfk-Institute has developed a rapid test for a simple and secure process control for surface disinfection so that an in-house self-monitoring is possible. This process control can be performed by cleaning and hygiene service providers without microbiological professionals and a laboratory.
In order to verify a successful disinfection procedure, visually detectable colour reactions were analysed. Such colour reactions have to be sensitive, fast, reproducible, clearly visible and stable for a certain period of time. Therefore dye releasing enzyme-substrate-reactions are suitable. The more active enzymes are available, the higher the released dye concentration is. It was proven that the reaction of proteases with a fluorescent substrate is a very sensitive detection method. The basis for the development of a rapid test were diverse inactivation kinetics of pathogenic and non pathogenic microorganisms due to disinfectants. To be suitable, the decrease of enzyme activity due to the effect of disinfectant has to correlate with inactivation kinetics of the different microorganisms.
Within the project, carriers consisting of a polyvinyl alcohol were developed which can be fixed reversibly on different surfaces (e.g. synthetics, stainless steel, glass) with a pressure sensitive adhesive developed by wfk-institute. Proteases were immobilised on the surface of the carrier in order to avoid spreading of enzymes by wiping during disinfection. After the disinfection step this functional models of a biomonitor can be removed from the surface. After the appropriate residence time a substrate solution has to be applied to the biomonitors. The biomonitors can be evaluated visually after a few minutes. By means of a colour scale it is possible to monitor the success or failure of the disinfection process.
Thus a rapid method is available for immediate evaluation of the surface disinfection without the help of external professionals. This method enables the cleaning service providers to increase the safety of the surface disinfection and to decrease the hygiene risk.
The IGF-project 16490 N of the research association Europäische Forschungsgemeinschaft Reinigungs- und Hygienetechnologie e.V., Campus Fichtenhain 11, D-47807 Krefeld, was supported via the AiF within the funding programme „Industrielle Gemeinschaftsforschung und –entwicklung (IGF)“ by the Federal Ministry of Economic Affairs and Technology (BMWi) due to a decision of the German Parliament.
The research report is available on request from FRT.