A Performance Test for Rating Dishwashing Detergents

Abstract

Microscope slides, after careful cleaning, were coated with a film of a standard mixture of natural food substances to which a measured amt. of ink had been added. The mixture was baked on at 95[degree]C for 1 hr., then washed at 140[degree]F in a specially-built machine constructed to give a maximum of measurable effect of the washing procedure using a series of different detergents compared with distd. water alone. A diagram of the machine is included. After rinsing and drying the slides were read for light absorption in a photoelectric cell. The method gives highly reproducible results and is judged to be a very accurate means of determining the effectiveness of various detergents.