Is bad breath caused by bacteria?

Chris - Absolutely, the bacteria that live in our mouths and metabolise what we put into our mouths and their metabolites are smelly. They can also be helpful because scientists showed in the last six months that they also give certain wines that lovely, what's called, retro aroma. The taste of the wine coming on in your mouth after you've swallowed it. Scientists showed that the bacteria break down sulphur compounds that are previously flavourless. As soon as you put them in your mouth the bacteria break down the compounds into smelly, whiffy compounds and that gives you the extra taste and extra dimension to a fine wine.