Rare hamburger is dangerous
It depends. A lot of attention has been given to the dangers of eating a burger that hasn’t been thoroughly cooked. There’s good reason for this. Commercial ground beef is made in factories in huge batches, and a single burger can contain meat from dozens or hundreds of individual animals. The chance of bacterial contamination making it into your supermarket package not insignificant, and this is a risk that many people don’t want to take. In fact, some states have banned restaurants from selling burgers that are not well-cooked. Too bad, because real burger aficionados know that the best tasting burgers are cooked to medium at most.
Is there a way around this? Yep—grind your own beef. If your ground beef comes from a single chuck or sirloin roast (or a mix of the two, my favorite), there’s a vastly smaller chance of contamination. You must observe proper procedure, making sure your grinder is spotlessly clean and keeping everything cold, of course. Buy your meat from a reputable, high-turnover retailer. There’s no absolute guarantee against contamination, of course, but the risks are much, much lower this way and your can enjoy a juicy, pink-in-the-center burger again.