Each consumer is entitled to have hygienically clean processed dishes and cutlery. Consequently, restaurants, caterers, canteens, nursing homes, kindergartens and hospitals are very concerned to avoid infecting their customers and patients. They are afraid of the spread of diseases by inadequately washed dishes, glasses and cutlery. This study deals with the verification of the hygienic performance of commercial freshwater dishwashers with the aid of bioindicators that are contaminated with the test soil BAMS and two different strains of microorganisms: Micrococcus luteus and Enterococcus faecium. The method used is described in the working paper “WD 00429001 Commercial warewashing machines – Hygiene requirements and testing.” Tests for heat resistance are carried out to check the temperature interval of Micrococcus luteus. Thereby, it is shown that the germ examined still shows vitality at a temperature of 70°C and a holding time of ten minutes. When testing the hygienic performance of the dishwashing programs tested, it is shown that not only temperature, but also the effects of the detergent are recognizable.

In recent years, the aspect of hygiene has become increasingly important in all areas of daily life. Especially in the areas of gastronomy, nursing homes, kindergartens and hospitals, the hygiene aspect is of particular importance. This study deals with the examination of the hygienic performance of commercial dishwashers with a water replacement system (fresh water dishwashers) using Micrococcus luteus DSM 1790 and the carrier material oat flakes as test soil. After rinsing, the soil is detached from the test items using an elution solution. Furthermore, the sump and the back and side walls of the commercial fresh water dishwasher were examined by contact plates to obtain the microbial count. This approach has been tested for functionality in a series of empirical experiments. In addition, the influence of various commercial detergents on results was examined. It was found that the newly developed method emphasizes the difference between the tested programs. Furthermore, it was found that using a program with longer holding times led to a higher germ reduction in the upper basket than in the lower basket.