Ian Fortey reports for the Asylum blog on the 5 edible things borne from crap you’d never eat. The edited list is below.

• Tilapia
Tilapia are little fish found pretty much all over the world at this point in farms and in freshwater, swimming about innocent as you please and occasionally winding up on the menu at Red Lobster. In countries like Vietnam, tilapia is a great crop for fish farmers as it is what is known as a "value added" crop, meaning not only can the fish be raised and sold for food, they also eat poo.
Like your strange cousin whom you were never allowed to be alone with, tilapia will put anything in their mouths. People exploit that by using tilapia for sewage treatments, where they clean up crap as they grow before getting sold to some lucky diner to eat with a side of mashed potatoes and a biscuit.
Research has shown that fish raised on poop will have significantly higher levels of fecal choliform bacteria in their tissue than fish raised in treated water, but the bacteria doesn’t seem to affect the muscle tissue, meaning the fish is more or less safe for you to eat. And, if it was raised in your neck of the woods, or at least where your toilet drains, it may even taste familiar.

• Citric Acid
If you’ve ever licked the walls under a sink in a condemned building, you have issues. But it’s also likely you’ve been horribly exposed to Aspergillus niger, one of the most common molds known to man, strains of which supply the bulk of our citric acid supplies.

• Pruno
You can’t really expect a prison to offer up the finest in wines, but even by prison standards pruno is kind of disgusting and, according to Wikipedia, is occasionally described as tasting like a "vomit-flavored wine cooler."
Because pruno is made in facilities where alcohol is not allowed and none of the tools to produce it are afforded to anyone, its production is a little more slapdash than your average bottle of Thunderbird. Basically, pruno is made from the remnants of whatever biomatter a felon can get his hands on — fruit salad, oranges, bread or anything that has the ability to ferment.
Once everything is smashed into a bag together, it needs to be kept warm for a few days, and then sugar has to be added. This can be real sugar, ketchup, honey, whatever is handy again, because this recipe is going to be disgusting no matter what. A few more days of being kept warm and voila, you have fermentation. Filter out the chunks of pulp and mold (because there will be mold), perhaps through an old sock, and there you have it, your own glass of awful, awful pruno. Enjoy as you try not to go blind.