The USDA recommends a series of temperatures to which beef, pork, lamb, and poultry should be cooked. The numbers are designed to protect consumers from pathogens, such as salmonella, E. coli, and many others, which can cause food-borne illnesses, some of which, in extremely rare cases, are fatal.

Safety experts and professional cooks say that adhering to the USDA's standards is a must when preparing meat for young children, pregnant women, older individuals, and those with weakened immune systems. But when it comes to cooking for healthy adults, many chefs feel comfortable diverging from the USDA guidelines and cooking most cuts -- except ground meat -- to lower temperatures for the sake of better flavor.

"If you hit the perfect balance, where meat's cooked but not overcooked, the ability to enjoy the taste is tenfold," says Martha Stewart Living food editorial director Lucinda Scala Quinn. Lynne Gigliotti, an instructor at the Culinary Institute of America in Hyde Park, New York, says she and other instructors teach the USDA temperatures in class, but that rules may be more relaxed in working kitchens. "School versus the restaurant business is a little different," she says.

That difference is anywhere from five to 30 degrees lower than the USDA's standard, depending on the type of meat, the level of doneness, and whether resting time is taken into account. The exception is poultry. In April 2006, the USDA issued a revised recommended temperature for poultry, lowering it to 165 degrees from 180, a number that had been in place since at least the early 1980s, Van says. Scala Quinn says this is how she and many chefs have prepared poultry for years. Gigliotti is one of them. "I've been doing 165 the whole time," she says.