Yes, there is special test called the “Spit Test” and you do it like this, First thing in the morning, before you put ANYTHING in your mouth, get a clear glass. Fill with water and work up a bit of saliva, then spit it into the glass of water. Check the water in about 30 to 45 minutes. If you have a potential problem you will see strings (like legs) traveling down into the water from the saliva floating on the top, or “cloudy” saliva will sink to the bottom of the glass, or cloudy specks will seem to be suspended in the water. If there are no strings and the saliva is still floating after one hour, you probably have normal levels of yeast under control.