Temperature, pH, and Moisture Profiles During Cooling of 290-Kilogram Stirred-Curd Cheddar Cheese Blocks

Abstract

The temperature at 28 locations in each of two 290-kg blocks of stirred-curd Cheddar cheese in stainless steel hoops was monitored during 12 d of cooling at approximately 2.2°C ambient temperature. Percentage of moisture and pH were determined at 28 different positions in cheese blocks after 0, 24, 48, 144, and 240h of cooling at 2.2°C and at 15 different positions in cheese blocks after 0, 12, 24, and 48h of cooling at 2.2°C. Temperature, pH, and moisture profiles in the blocks were generated from the data. Vacuum treatment and heat of metabolism of starter bacteria may have affected block temperature before the start of cooling. Temperature gradient from the interior (mean of 35°C) to the exterior (mean of 15°C) of blocks developed within 24h. It took 12 d for the center of blocks to reach 2.2°C. Milk fat appeared to affect cooling rate. Gradients of pH and moisture extended from the interior (means of pH 5.40 and 41%, respectively) to the exterior (means of pH 5.25 and 39%, respectively) of blocks. After 24h, pH and moisture gradients were reversed and were lower in interior regions (means of pH 5.1 and 35%, respectively) than in outer regions (means of pH 5.2 and 38%, respectively). Moisture appeared to travel in response to temperature and pH gradients.