Recent research indicates that such chemicals as hydrogen sulfide, methyl mercaptan, as well as dimethyl sulfide contribute to bad breath. Collectively this group of chemicals is known as volatile sulfuric compounds. You may see them at times referred to by their abbreviation: VSC.
These chemicals are produced by anaerobic bacteria, which are found mostly on the back of the tongue. Think of bacteria as miniature living, breathing creatures. That essentially is what bacteria is.
They spend their lives "eating" or taking in nourishment, much like we do and then excreting the wastes. The waste products of these anaerobic bacteria are the VSC I've just mentioned.
So you're probably beginning to get a better idea why I'm talking not only about the Halimeter right about now, but tying it in with the life cycle of your bacteria and the resulting VSC waste.
Think about the smell of a rotten egg? Once you smell this distinctive odor you'll always recognize it. This specific -- and unique -- smell is caused by the sulfur compound hydrogen sulfide.
And yes, now that you mention it, it really is the same smell that comes from feed lots as well as barnyards due to the sulfur compound methyl mercaptan.
Another sulfur smell comes -- if you're familiar with it -- the smell of the ocean. This particular smell is due to the presence of dimethyl sulfide.
Each of these various types of sulfur compounds, by the way, is also excreted as a waste product by the bacteria that like to live in our mouths.