Having made certain that your physical oral condition is as pristine as possible by brushing and flossing and proper diet and all the other good things, your method of attack is as follows. 

1. Chew sugarless gum or suck on sugarless lozenges to increase saliva flow. Saliva is the mouth’s natural mouthwash; it has antibiotic elements in it which reduce the numbers of bacteria in the mouth. Sugarless gum or candy is an absolute must. I’ve seen horrible cases of decay and gum disease arise from the habit of frequently eating sugar containing foods. Some people learn how to milk the salivary glands by sucking on the cheeks or tongue.
2. When saliva production diminishes, keep the mouth wet with a liberal intake of water. Experts advise drinking eight glasses of water a day for basic metabolic function, and it seems that keeping the mouth moist is a good way of keeping the bacterial flora of the mouth under control. Hold the water in the mouth as long as possible-minimum of twenty seconds, and swish it around to loosen food particles and other bits of debris that bacteria feed upon. The longer the water remains in the mouth the better.
3. Snack on carrots, celery, or other vegetables to keep plaque from forming.
4. Vitamin C deficiency may be a cofactor-factor on bad breath. Smokers, especially should take regular supplements of vitamin C since the nicotine in the cigarettes destroys vitamin C. A better tactic is to stop smoking all together, but if you’re still puffing after hearing all the evidence, the fact that your own halitosis is polluting the air probably isn’t going to change you much.
5. What works in the refrigerator may work in the mouth. Consider brushing your teeth and tongue with baking soda. This is admittedly kind of gross. Any of several brands of toothpaste containing baking soda can be used instead and are more palatable.
6. A handy portable, battery powered version of the water Pik is available. It can be easily transported in a purse or brief case and is one of the most powerful and certain ways of preventing bad breath; it really knocks the food particles out from between the teeth.
7. Consider any of the over-the-counter mouthwashes which do the same thing as rinsing the mouth with water, but also add a bit of odor neutralizing substances such as cetylpyridinium chloride (CPC), zinc chloride (more about zinc in a bit.), or chlorhexidine. Look for products containing these compounds. Buying the mouthwash also makes the buyers a little wealthier, stimulates the economy, and maybe provides a sense of security. There is a prescription mouthwash called Peridex which seems to be a little more effective than the over-the- counter brands although its taste leaves something to be desired.
8. Before the big date, the business presentation, or the stress encounter consider rinsing the mouth with a 50/50 solution of hydrogen peroxide and water. A teaspoon of each is swished in the mouth for one full minute. Hydrogen peroxide releases free oxygen which is poisonous to many of the bacteria that cause bad breath. If things are really going to be tense, Maybe a tranquilizer or two might help also. (See your health care provider for advice on this)
9. Zinc and compounds of this metal have complex effects on the plaque forming process, and one researcher has suggested that zinc salts combined with ionone, an ingredient of tomato juice, appear to produce a much longer anti-plaque and anti-odor effect than either alone. Maybe those who favor bloody Mary’s, virgin or real, in the morning, have hit upon the definitive cure for the jungle mouth.
10. In those cases where hunger odor is present, the way of correcting the problem is simple: just have a bit to eat.