If you're determined to brave the bacteria and suck down that Christmas cup of calories (an 8-ounce serving averages around 250 to 300 calories), Dr. Mildred Cody, a registered dietician nutritionist (RDN) and food safety instructor emerita at Georgia State University, explains ways you can do it safely. "Don't count on alcohol in eggnog to kill all of the bacteria," Cody said. "That's not likely to happen." The answer, she says, is pasteurization.

Remember Louis Pasteur from grade school science class? He's the guy behind pasteurization, a process of zapping perishables like eggs and dairy at high heat just long enough to kill any wayward pathogens without affecting the quality of the food. But here's the thing: "Most eggs in [an American] grocery store are not pasteurized," said Elisa Maloberti, the American Egg Board's manager of food safety. "Pasteurized eggs will be clearly marked on the package."