I've never heard that one - bad breath is usually generated by stomach gas, or bacteria in the mouth, or in the worse cases, tooth or gum disease. The best way to check if you have bad breath is to choose a clean patch of skin - inside your forearm is usually best - lick the spot, leave it for a few seconds then sniff your skin. What ever you smell is how your breath smells at the time - no odour, no bad breath, niff like a docker's armpit - time to brush and floss, or see your dentist.