Hamburger Health

About 76 million people will get sick from food borne illnesses this year, according to the CDC, and 5000 will die. The annual cost in the U.S. is about $152 billion.
Burgers and other ground meats are particular havens for pathogens because salmonella, E. coli, campylobactor, listeria and other bacteria lurking on the surface of the meat get ground into the interior, where it's more difficult to make sure they are being killed by cooking. Store ground beef at 40 degrees or below and use or freeze within 2 days.
E. coli colonizes in the intestines of animals and can contaminate meat at slaughter. These dangerous bacteria can survive and multiply in cold conditions; as low as 44 degrees. E. coli grows rapidly in the warm setting of a picnic or outdoor party and can cause serious illness and death. E. coli can live on a dry, stainless steel surface for 6 months - imagine what it can do in a campground! Rare burgers are a major risk. To completely destroy harmful bacteria, cook burgers to an internal temp. of 160 degrees. Use a meat thermometer to make sure. When reheating previously cooked meats, internal temp. should be 165 degrees. Remember to wash hands when handling food; it's easy to forget when you're out doors or camping.
~ Center for Disease Control