Is it safe to eat a hamburger rare or medium-rare?
Generally – no, but not impossible to be done… safely.
Here is what you need to know. Harmful bacteria lives only on the surface of meat cuts, like steaks. But, when meet is ground, the surface (possibly contaminated) penetrates in the middle, dispersing the potentially illness-causing pathogens inside the ground meat.
denaturing of meat protein
When you order a rare stake at the restaurant, it is always thoroughly cooked on the outside. That takes care of the “bacteria and pathogens” deal. But when you order a burger it always comes well-done (or at least it should). So, this is the reason.
How should you cook your hamburgers at home? Well-done. You can still make them juicy. All you need to do is bring the center of the burger to 170°F (pasteurization temperature). At this temperature pretty much all pathogens are gone. Of course you won’t be able to use a cooking thermometer to check the temperature (in roasts – yes, but not in burgers – not enough depth).
So, how can you tell that you’ve reached the “safe to eat ground meat” temperature? When you break one open there shouldn’t be any pink left. The meat should be brown-gray in color and the juices that come out – clear. At this temperature the meat protein myoglobin denatures and the color of the meat changes to brown-gray.
What if you still want your hamburger rare?
There is a way. You have to grind your own meat LAST MINUTE, but before that you have to sterilize the surfaces (remember, pathogens live on the surface only in whole muscle meat cuts). First, you bring a pot with water to a boil. Next, blanch the meat cuts for 30-60 seconds. Pat dry. Grind right away, using a CLEAN meat grinder.
With this method you will have a meat with sterile surface that is not thoroughly cooked – only the outer 1-2 millimeter layer will be cooked. When ground the meat will still appear raw. Now you can leave the center of your burgers rare or medium rare – whichever you prefer.
Either way – enjoy… and, let me know if you give the “rare hamburger” process a try.
Resource: Harold McGee “On Food and Cooking: The Science and Lore of the Kitchen” – The “Bible” of the cooking science lover