Bacterium that produces VSCs are usually Anaerobic.

Bacterium that produces VSCs are usually Anaerobic (bacteria that live in conditions where there is no oxygen). They are found in the airless places in the mouth: Crevice, Folds and pockets, and especially in the surface of the tongue, where they live deep between the Studded papillae taste bud. Getting rid of bad breath means getting into the Hiding Place where multiply these bacteria, and killing or removing them. To get rid of bad breath, you have to clean up your mouth.
For some people, its just a matter of improved oral hygiene. Flossing and brushing regularly, having tooth and gum problems attended to, and cleaning of the tongue may be all it takes to get rid of bad breath. In more complicated cases, getting rid of bad breath may require the use of other products, such as mouthwashes, special toothpastes, or antibacterial solutions.