A computer vision system was used to evaluate the melting property of cheese. The method is suitable for both cheddar and mozzarella cheese. The effect of cooking time (0-20 min) and temperature (70-200degreesC) on the melting degree and melting rate of cheddar and mozzarella cheese was investigated and the melting property of both cheeses were compared. Both cheddar and mozzarella cheese melted rapidly at the initial stage of cooking and melting slowed down in about 3-4 min. Maximum melting degree and melting rate occurred at about 130-160degreesC. Extended cooking and cooking at high temperature may cause reduced melting. Cheddar cheese melted more rapidly and considerably than mozzarella cheese at all cooking temperatures. (C) 2002 Elsevier Science Ltd. All rights reserved.