The images may not be gross, but what you are about to learn will be.

Enter: The common house fly. A mild annoyance, always trying to land on your food. Whip out the fly swatter and the problem is over right?

Fly's are unmatched when it comes to habouring and spreading diseases to humans. When a fly lands on your food, the fact that it's toucning your food shouldn't concern you; it's what it does on your food should. Flys for one frequently deposite their feces on food. Also fly's have very primitive digesttive systems, they cannot intake solid food. Nor do they have pre-stage disgestion like humans and their saliva do. So a fly has to vomit digestive acids (barf in common terms) on the food to be able to devour it.

Ever wonder why flys hang around excrement so much? Well it's their offspring that depend on it. Fly larvae (maggots) eat bacteria as their main nutritional source, and feces are full of it. So the next time you see a fly hanging around your weekend barbecue, note that your hamburger has fly vomit, fly feces, and bacteria on it. Enjoy your meal.