Cleanability of Milk-Filmed Stainless Steel by Chlorinated-Detergent Solution

Abstract

Stainless steel test plates, with and without pretreatment in 100ppm chlorine, were filmed with cold raw milk and washed by 16 detergents at 0.35% concentration. The detergents ranged from 0.016 to 0.102%, active alkalinity and 0 to 100ppm available chlorine.Plates filmed with milk only were cleaned effectively by each nonchlorinated detergent, but high soil build-up, appearing as blue-brown color, accumulated when washed in alkaline solutions containing 25ppm available chlorine. Less build-up occurred from 50 and 54ppm chlorine and none from 75 and 100ppm.Plates filmed with milk following pretreatment with 100ppm chlorine accumulated high build-up when washed by alkaline detergent solutions. High build-up occurred as well using alkaline solutions supplemented with 25ppm, and somewhat less with 50ppm. None occurred when alkaline solutions contained 75 and 100ppm chlorine.Soil build-up was caused by adhesive nonsoluble chloro-protein occurring in low concentration of chlorine ions. When the concentration of chlorine ions increased to 75 and 100ppm the chloro-protein was solubilized and nonadhesive.