Here at MIT, we're doing a science journalism boot camp this week on food. And I've already picked up my first troublesome factoid: Hamburgers that look well done, observes J. Glenn Morris, Director of the Emerging Pathogens Institute at the University of Florida, aren't necessarily safe. In his lecture this morning, Morris observed that while cooking meat at a temperature of 160 degrees kills pathogens like the dangerous E. coli 0157:H7, 25 percent of hamburger patties will appear cooked at lower temperatures than that. Therefore, not only are rare or medium rare patties not necessarily safe to eat, but even a brown color shouldn't inspire full confidence. In truth, you need a food thermometer to be sure you've got a well cooked hamburger. And nobody whips those out before digging in at a fast food or pubby food restaurant. I know I don't, and I eat a lot of hamburgers. Or at least, I used to. More technical details here.