Industrial hood-type dishwashers play a key role in the hygiene and washing of dishes in industrial, hospital, and restaurant settings. However, optimization of operational and geometrical parameters of these machines has received less attention. The aim of this study is to experimentally investigate and optimize six key parameters including temperature, pressure, number of nozzles, arm angle, arm rotation speed, and type of washing liquid on the percentage of remaining stains and the number of microorganisms in a hood-type industrial dishwasher. Experiments were designed and conducted using the Taguchi design of experiments method (L18 array) and Qualitek software. Each parameter was examined at three levels. The percentage of remaining stains was measured through image processing in MATLAB software using the Otsu thresholding method. The number of microorganisms was counted through culturing samples taken from dish surfaces. Data analysis was performed using Analysis of Variance (ANOVA) and main effects plots. The results showed that reducing pressure and the number of nozzles leads to reduced stains, while increasing the angle increases stains. Rotational speed initially increases and then decreases stains. The combination of baking soda and vinegar had the best performance in stain removal. Regarding microorganisms, increasing temperature reduced the number of colonies, but reducing pressure and the number of nozzles increased microorganisms. Water alone, due to the short washing time (1 minute), performed better than detergent in reducing microorganisms.