You may not want to buy that soda from your local fast-food joint. Today, there's growing news coverage that commercial soda fountain machines may contain "coliform bacteria" which is banned by the FDA since this type of bacteria may well contain fecal matter. That's right -- fecal matter.
Right now, this horror is based upon a study done of a mere 30 soda fountains in the Roanoke Valley of Virginia. However, statistics being what they are, many are extrapolating that study and seeing it as having national implications.
What's causing this? Apparently, there is a little plastic gizmo (i.e., nozzle) that connects with a plastic tube that carries the liquid from the storage container through the tube and nozzle, into the glass. (Think about the self-serve fountains at the theatre or the convenience store.) Just one "contamination" of that nozzle can allow the bacteria to spread and grow within the plastic tubing, and apparently, the tubing doesn't get cleaned all that often.