The Calgary Herald posts a report about a new hand scanner that
causes fecal matter to glow. After you wash your hands, you stick them under this scanner, and any feces or similar germs will glow slightly, telling you that you are impure and, if allowed to handle food, will go on to kill millions of people.

The device was initially developed by a company called
VerifEYE to detect the presence of chlorophyll, a plant-matter compound that is found in cow feces (because they're herbavores). If you're working in a slaughterhouse and you have cow poop on your hands (or maybe if you just ate a carrot or something), the residue on your hands will glow under this scanner. But what about detecting human feces, if the human hasn't eaten a salad lately?
Says the article: "We're looking at scanning multiple substances from the fecal material" -- a variety of chemical compounds common to most human foods, but which are absent from skin cells. Once again, there's a fluorescent glow under the right light.
This is great. The next step is personal handheld devices so you can scan your food for fecal contamination before you eat it. But here's the real gold mine: toilets with the lights built in under the rim. You take a dump, turn out the lights, and watch your crap glow as it swirls down the toilet. In fact, I can picture a nightclub with transparent sewage pipes leading throughout the venue, so you can watch glowing turds make their way through the air as you party.