Potentiometric Studies with Resazurin and Methylene Blue in Milk

In these studies, the errors resulting from undisturbed creaming (3, 7, 10, 13) were minimized by inversion of tubes at regular intervals until incipient reduction was noted.The wider ratio (1: 2) reported by Collins et al. (1) may be due to their incubating tubes undisturbed, or to end-point differences.Reduction time for resazurin represents the time taken to change to a full pink color; for methylene blue, the time required to decolorize at least 90 per cent of the column of milk.295