Development of a biocatalytic color indicator system for process control of disinfection in commercial dishwashers
IGF 17664 N
The requirements for hygiene in the food sector arise from the EU regulation on the hygiene of foodstuffs i.e. (EC) 852-854/2004, which require a hygiene management system based on the HACCP concept (Hazard Analysis Critical Control Point) for canteen kitchens and many other areas.
Dishwasher processes are recognized as important Critical Control Points within these hygiene management concepts and must be controlled periodically, for which the operator has to take care.
However, end product and in-process controls described in respective standards (e.g. DIN SPEC 10534) exhibit major disadvantages. These disadvantages result from the use of conventional microbiological culture methods providing results only after several days. This testing is expensive and requires a microbiologist and a lab. A simple and quick method for routine control is not available.
In the course of the project a new rapid assay system for the process control of dishwasher processes was developed, wherein the specific activity of enzymes is displayed by dye systems. Since germicidal processes are based predominantly on protein denaturing effects, germ killing can be represented by the denaturation of enzymes.
Functional samples of the developed enzymatic process challenge devices consisted of porous ceramics with a height of 1.2 cm and a circumference of 4.5 cm. Loaded with enzymes they demonstrated a good agreement with in-process controls based on microbial inactivation, both in the laboratory and in practice (exemplary application at 6 mass catering facilities). Within about 10 minutes the developed system allowed the evaluation of disinfection performance of dishwashing processes by visual analysis of coloured reaction products released from chromogenic substrates.
The rapid test is inexpensive and does neither require skilled microbiologists nor a laboratory. The hygienic safety in dishware disinfection will be increased by using this rapid test system, which easily enables frequent in-process controls.
The IGF-project 17664 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 Energy (BMWi) due to a decision of the German Parliament.
The research report is available on request from FRT.