Is it rare to find a well-done burger?

In the past few months, on three occasions I've noticed restaurant burgers that were pinkish-red in the center.

In the first case, it was a plump bison burger I ordered for lunch at the Metropolitan. When I asked the manager about the pinkish interior, he told me the restaurant cooks bison burgers to "just past medium." He assured me that the staff grinds the bison on the premises, so they feel confident about its safety.

I realize that bison (or buffalo) is very lean, so it's dry and sawdusty when overcooked. But I've always been a well-done wimp, having done my share of stories on E. coli and salmonella poisoning. I feel better sacrificing a little juiciness in order to avoid any pink in my burgers — bison, beef or otherwise.

In a second case, I took a co-worker out to lunch at Bambara. The outside of his burger was browned, but the center was reddish-pink. He asked the waiter to have it cooked through, which was done without hesitation.

In the third case, I was at The Counter, a new burger restaurant at The Gateway. As we were ordering, the waiter told us that beef burgers there are always cooked to medium, so you should expect to a little red in the center, adding, "because we know where our beef comes from."

I said that was all well and good, but I still prefer my ground beef cooked to well-done. The waiter was OK with that. My burger came out with a grayish interior, but I thought it was still juicy and flavorful.

In all three cases, they were higher-end burgers costing at least $9 apiece. Maybe it's because I don't usually order them outside of fast-food restaurants, but I just assumed that burgers were supposed to be cooked "well-done," all gray in the center, without having to specifically order them that way.

When ordering steak, you're asked your preferences on doneness — rare, medium, well-done. That's because theoretically, the inside of the meat carcass is considered sterile and the outside is seared to kill any germs that the outside of the meat may have been exposed to.

But with ground meat, the sterile inside and possibly contaminated exterior of the meat gets ground up and mixed up together.

The U.S. Department of Agriculture's food safety fact sheets say restaurants should cook ground beef to at least 155 degrees, with the meat being mostly gray inside. It adds that color is not always a good indicator of doneness, because really lean ground beef might remain pink at temperatures above 160 degrees, and other beef may look brown and fully cooked before it reaches the proper temperature. In fact, according to USDA research, one in every four hamburgers turns brown before it reaches a safe internal temperature.