Our mouth is home to thousands of germs and bacteria so is there any wonder that our breath may not be so fresh from time to time.  Food and drinks can have an immediate effect on our breath though not normally long lasting.   

What you should take note of is when you have bad breath that lasts more then a day or keeps coming back shortly after brushing your teeth.  Bad breath can be a sign of other oral issues, such as tooth decay, gum disease or dry mouth. See a dentist if you are worried about what you bad breath may be telling you.