Development of a Method for the Analysis of Microbial Load Reduction Factors on Dishes Cleaned by Hand and by Machine

Abstract

Abstract The aim of this study was to develop a repeatable method for the measurement of microbial load reduction factors after hand and machine dishwashing processes that meet the requirements associated with consumer studies, based on non-pathogen test strains. Microorganisms were isolated from tableware, identified and cultured for this purpose, mixed with soiling agents and lyophilised for storage purposes. Detailed instructions for ambient conditions and disinfection, and preparation and application of soiling agents were defined. The method chosen in this study successfully led to repeatable results. The food matrix of the soiling agents used for the application of test strains shows to have a large impact. This is, therefore, the first repeatable method that enables the comparison of microbial load reduction factors after machine with hand dishwashing. In addition, the method was designed in a way that enables further consumer studies.