Adenosine 5′-Triphosphate Content of Streptococcus mutans GS-5 during Starvation in a Buffered Salt Medium

Adenosine 5′-triphosphate (ATP) of Streptococcus mutans GS-5 was studied by the firefly bioluminescence method during starvation in a buffered salt medium. There was a decrease in the cellular ATP content with time. The rate of decrease was significantly greater at 37 °C than at 22 °C. The loss in ATP was not accompanied by a decrease in cell number. This variation may lead to errors in the estimation of viable plaque mass by ATP measurement.