A Test for the Keeping Quality of Pasteurized Milk1

A simple color test, capable of detecting pasteurized bottled milk having poor keeping quality under refrigeration, is described. Neotetrazolium dye is mixed with milk in a test tube. The tube is evacuated and sealed, placed in an incubator at 37° C. and examined after four hours. A detectable pink color appearing in the sample is an indication that the milk will undergo flavor spoilage within a four day period. This test apparently measures the psychrophilic activity in the milk.