The effect of operating conditions of a vacuum cooler on the cooling performance for large cooked meat joints was analysed by a validated mathematical model. The simulation shows that the cooling rate varies mainly with three parameters, chamber free volume, pumping speed and condenser temperature. The cooling rate increases with the pumping speed and decreases with the other two parameters. If no vapour condenser is used, it is difficult for the pumps to remove the large amount of vapour generated. The transient condensing load significantly depends on the cooling rate. An increase in cooling rate will increase the transient condensing load. However, the operating conditions have a negligible effect on weight loss during vacuum cooling. (C) 2003 Elsevier Ltd. All rights reserved.