What gives bad breath its smell? The chemistry of halitosis

Apparently, few things can ruin the chemistry between two people more effectively than the chemistry of bad breath. Fortunately, scientists are working on what exactly causes halitosis, as well as which chemicals cause the odors of special kinds of halitosis.

Let's start with coffee. A recent Harlequin Survey found that 49 percent of men and 62 percent of women think that oral odor caused by a cup of java is the number-one turnoff, as reported by the Toronto Sun.

Where does the odor of coffee breath come from? In essence, nearly any food can cause bad breath simply by giving oral microbes something to eat. These bacterial colonies are semi-permanent fixtures in the mouth, usually only disappearing if new, more productive microorganisms are introduced to the palate via oral care probiotic products.

However, coffee breath has a specific scent. This comes from several organic compounds found in the the beverage. One is called 3-mercapto-3-methylbutylformate (3M3M), according to the Coffee Research Institute (CRI). It is a molecule closely related to methyl mercaptan. If you've ever smelled rotten cabbage, you know what methyl mercaptan smells like.

Coffee contains lots of 3M3M, typically about 0.3 milligrams per liter of the drink, according to the CRI. With this compound coating your tongue and teeth, you're almost guaranteed to have halitosis. The Good Scents Company, which lists the odor properties of the molecule as "catty" and "sweaty," puts it succinctly: "Not for fragrance use."

Garlic breath comes from another methyl-group compound, one called allyl methyl sulfide (AMS). Unlike 3M3M, which is usually described through analogies to other smelly things, AMS smells like one thing only - garlic.

Eat some garlic, and your mouth will almost assuredly reek of AMS. Rinsing with a specialty breath freshener is one effective way to eliminate this odor before it becomes problematic.

Finally, researchers have recently looked into the chemical content of fish, and fish breath. To do so, a group of scientists from Spain and India prepared samples of anchovy sauce and then analyzed them using miscellar liquid chromatography, a technique that reveals a sample's chemical contents.

The group found that anchovy sauce contains between 0.5 and 2 parts per million (ppm) of putrescine, an aromatic molecule that gives rotting meat its distinctive aroma. They noted that the 2 ppm sample had probably spoiled. Fish breath, as well as breath scented with other meats or cheese, is likely to be loaded with putrescine.

Using a specialty breath freshening product can tip the chemical balance of your mouth away from halitoses of all kinds.