There are over 500 bacteria strains in the mouth - some beneficial and some detrimental. A handful of those bacteria lead to foul breath due to the sulfurous odors they produce, with the anaerobic bacteria at the back of the tongue contributing the most to halitosis.
Everyone can and does have bad breath at some point. Halitosis can be caused by:
• The breaking down of food remnants around the teeth and gums
• Less saliva in your mouth
• Tobacco or alcohol use
• sinus problems
• Dental issues such as decay or periodontal disease and personal hygiene.
A dry mouth can fe an especially ripe environment for dead cells to accumulate on the tongue, gums and teeth, causing odor as they decompose.
Food can be a factor too. After foods are digested they go into the bloodstream, where they are carried to the lungs and come out through your breath. Onions and garlic, for example, can cause bad breath for 72 hours after eating them, while high-protein foods and dairy products can provide a breeding ground for bacteria to grow, increasing your risk for bad breath.
On the good side, foods such as nuts and seeds, parsley, mint, crunchy fruits and vegetables and raisins assist in combating dragon breath. Drinking plenty of water and tea or a bit of cranberry juice can be beneficial as well.