Transformers change the voltage, but not the supply frequency (60Hz in America, 50Hz in Britain). For smaller motors which are used relatively infrequently, such as those found in food mixers, blenders, etc., it's seldom a problem, but the frequency difference becomes much more significant with larger motors.
Expect reduced efficiency and a motor which gets warmer than usual if you run a 60Hz fridge compressor on 50Hz. Bearing in mind the continuous (albeit cyclic) operation of a fridge, this is one application where I really wouldn't recommend it without more detailed information about the motor.