Predicting the cutting time of coagulating milk for cheese production using a heated thermistor

Based on an observed decrease of effective thermal conductivity of milk dur ing coagulation, a heated thermistor sensor was developed for monitoring cu rd formation. The thermistor was heated with a constant direct current, and its voltage was measured during milk coagulation, indicating a drop after the enzymatic reaction. The sensor was studied in the laboratory for differ ent milk acidities, rennet concentrations, added calcium chloride, and coag ulation temperatures. It was also tested in a commercial cheese plant for m ore than a month. The cutting time established by the cheesemaker in 16 exp eriments was compared with a prediction equation, and the standard error of prediction was 1.9 min.