It might not be the garlic or onions, coffee or alcohol. Rather, a new study links it to the types of bacteria that dominate the back portion of the top of your tongue.

Some bacteria protect against halitosis, the formal name for really bad breath, while others cause the pungent¹ odor, says a team of researchers from The Forsyth Institute in Boston.

"I think there's a definite smoking gun here -- that it's a strong association," says lead researcher Bruce Paster. "There are the good bacteria and the bad ones."

The study, reported in the February issue of the Journal of Clinical Microbiology, relied on gene² sequencing to compare bacteria found on the tongues of those with halitosis and those with fresh breath.

Researchers reported species of the same three bacteria were prevalent among five people with fresh breath. The most common of these germs found on these subjects' tongues, Streptococcus salivarius, appeared in only one of six people with halitosis -- and at extremely low levels.

Six species of bacteria were linked to halitosis, and several of those germs were not found in those with fresh breath.

About 65 million Americans suffer from halitosis at some point in their lives, the National Institute of Dental Research has estimated.