Hamburgers

The dirt: Your standard hamburger can be quite nasty. A U.S. Department of Agriculture report found traces of Ivermectin, an animal wormer that can cause neurological damage in humans, as well as arsenic and other veterinary drugs, in beef sold in the U.S. Heating the meat at high temperatures could cause those chemicals to become even more dangerous.

Fix it: Buy organic beef, or choose grass-fed beef certified by the American Grassfed Association or beef that's Animal Welfare Approved. Grass-, not grain-eating cows are less likely to harbor lethal strains of E. coli, since grass promotes healthier pH levels in the animals' gut.