Effect of cooking and cooling method on the processing times, mass losses and bacterial condition of large meat Joints

This study compares the heating and cooling times of and mass losses from meat joints in three systems: convective air, water immersion and pressure/vacuum. Cooling times were compared with the UK Department of Health (DoH, 1989) guidelines which state that joints should be cooled to 10°C or below in less than 150 min.
Five types of joint were used: 50-mm thick (0.94kg) slabs of beef m. semitendinosus, 2.7kg rolled beef forequarter and silverside, 6.4kg rolled turkey and 7.1kg boned-out ham joints. Six replicates of all joints were cooked from 5 to 75°C (beef), 80°C (ham) or 85°C (turkey) and then cooled to a maximum internal temperature of 10°C.
Average cooking times for convection, immersion and pressure were 263, 278 and 135 min, respectively. Average cooling times for convection, immersion and vacuum were 433, 298 and 50 min, respectively. Vacuum cooling times did not depend on joint size but may have been affected by porosity of the meat. The DoH guidelines could be achieved by immersion or vacuum methods when cooling the small beef slabs but only vacuum cooling was sufficiently rapid when cooling the larger joints.
Mass losses due to pressure cooking (mean 37.4%) were greater than those during convection heating (28.9%). Vacuum cooling resulted in an average mass loss of 8.2% but losses were smaller after convection cooling (2.5%). Average total viable counts (log10 no. of bacteria cm⁻²) after processing and 12h storage were 1.0 at both the surface and interior.