Re: Can I take a more accurate amount than a swab from inside my mouth?

Katie - your science project sounds very interesting :-)

I have a couple of ideas that may help you in developing a method to take a more accurate swab from your mouth. Normally, when swabbing a surface to check for microbial growth, a designated size is swabbed; for example, one square inch. For your mouth (or other people's mouths) this may prove to be a bit difficult since you can't really see what you are doing.

Originally I thought that maybe you could use a piece of sturdy plastic with a window cut out of the center (say one square inch), this way the only part that you would swab would be that one square inch. Again, this may be difficult to hold in the mouth while swabbing. Another method would be to swab for a given amount of time (say 10 seconds) or to take a given number of strokes (say 15 strokes). These may be a little less accurate, but easier. If you use either of these methods, then you will also want to keep your stroke lengths similar. So which ever method you decide to use, you can document this in your materials and methods as such (i.e. To take a sample, swab the inside of the cheek for 15 times where each swab stroke is about 1 inch).

A couple of other points (which you may already be doing)... make sure that the person doing the swabbing has clean hands (so contamination is reduced), also, if you are checking the efficacy of these mouthwashes, are you doing so at the same time everyday (say when you get home from school)? This way, the bacteria in your mouth (between mouthwash testing) will have had the same amount of time to grow. I hope that these ideas are useful to you! Best of luck in your county science fair :-)

Glynis

Food Microbiology, Graduate Student