Brush after every meal, and start using an antimicrobial mouthwash if you don't already. Even if you stay away from garlic and onion, any type of food can contribute to bed breath when it reacts with your saliva and oxygen. Start carrying a travel kit with a brush, toothpaste, and mouthwash to use at thee office or on the road between meals. Particles of food left by not brushing and flossing often begin to feed bacteria and encourage their growth, causing bad breath.