The ratio of the different types of S. aureus surviving cells immediately after sub-lethal heat treatment (52 degrees C for 15 min) was studied. A high ratio of cells which are unable to form colonies even in a common medium such as TSA was observed. This fact has not been reported previously for common media through recovery after heat shock has been widely studied. After the treatment, staphylococcal protein A, but no enterotoxin, was seen to be released into the extracellular environment.