A new test method to assess the cleanability of open process equipment

The hygienic design of food processing machines and facilities is essential for ensuring food safety, as it enables reliable and efficient cleaning. While a standardized laboratory test procedure for assessing cleanability is available for closed equipment, comparable methods for open equipment are still lacking. This study aimed to develop and validate a practical test method for evaluating the cleanability of open food processing equipment. The developed procedure is based on the application of a fluorescent food model soil, reproducible spray cleaning using a robotic system, and detection of residual soil by image analysis. To ensure reproducibility and validity, a reference item containing both hygienic and non-hygienic design features was developed. In addition, different machine feet representing exemplary industrial machine components were investigated as test items. The test method was successfully applied to both the reference item and the machine feet. Areas designed according to hygienic design principles could be clearly distinguished from areas with poor cleanability. The results demonstrated good reproducibility and showed that the combination of standardized soiling, automated cleaning, and image analysis enables a reliable assessment of cleanability for open equipment. The developed approach closes an important methodological gap in the evaluation of hygienic design for open food processing equipment. It provides a reproducible, industry-relevant, and practical method for assessing cleanability and may support the hygienic optimization and validation of industrial equipment.